Avoid meta programming to initialize functions in module scope (#26388)

I'm trying to get rid of all meta programming in the module scope so
that closure can do a better job figuring out cyclic dependencies and
ability to reorder.

This is converting a lot of the patterns that assign functions
conditionally to using function declarations instead.

```
let fn;
if (__DEV__) {
  fn = function() {
    ...
  };
}
```
->
```
function fn() {
  if (__DEV__) {
    ...
  }
}
```

DiffTrain build for [d310d65](d310d65)

compiled/facebook-www/JSXDEVRuntime-dev.classic.js

@@ -941,7 +941,7 @@ function defineRefPropWarningGetter(props, displayName) {
  * @internal
  */
 
-var ReactElement = function (type, key, ref, self, source, owner, props) {
+function ReactElement(type, key, ref, self, source, owner, props) {
   var element = {
     // This tag allows us to uniquely identify this as a React Element
     $$typeof: REACT_ELEMENT_TYPE,
@@ -993,7 +993,7 @@ var ReactElement = function (type, key, ref, self, source, owner, props) {
   }
 
   return element;
-};
+}
 /**
  * https://github.com/reactjs/rfcs/pull/107
  * @param {*} type

compiled/facebook-www/JSXDEVRuntime-dev.modern.js

@@ -941,7 +941,7 @@ function defineRefPropWarningGetter(props, displayName) {
  * @internal
  */
 
-var ReactElement = function (type, key, ref, self, source, owner, props) {
+function ReactElement(type, key, ref, self, source, owner, props) {
   var element = {
     // This tag allows us to uniquely identify this as a React Element
     $$typeof: REACT_ELEMENT_TYPE,
@@ -993,7 +993,7 @@ var ReactElement = function (type, key, ref, self, source, owner, props) {
   }
 
   return element;
-};
+}
 /**
  * https://github.com/reactjs/rfcs/pull/107
  * @param {*} type

compiled/facebook-www/REVISION

@@ -1 +1 @@
-6bd53a5bdfe24d9a70819c4eba40b488e62900cd
+d310d654a7c7aab6c8213da84ef36dfba82711b0

compiled/facebook-www/React-dev.classic.js

@@ -27,7 +27,7 @@ if (
 }
           "use strict";
 
-var ReactVersion = "18.3.0-www-classic-96f33629";
+var ReactVersion = "18.3.0-www-classic-e762d1a9";
 
 // ATTENTION
 // When adding new symbols to this file,
@@ -756,7 +756,7 @@ function warnIfStringRefCannotBeAutoConverted$1(config) {
  * @internal
  */
 
-var ReactElement$1 = function (type, key, ref, self, source, owner, props) {
+function ReactElement$1(type, key, ref, self, source, owner, props) {
   var element = {
     // This tag allows us to uniquely identify this as a React Element
     $$typeof: REACT_ELEMENT_TYPE,
@@ -808,7 +808,7 @@ var ReactElement$1 = function (type, key, ref, self, source, owner, props) {
   }
 
   return element;
-};
+}
 /**
  * Create and return a new ReactElement of the given type.
  * See https://reactjs.org/docs/react-api.html#createelement
@@ -3574,7 +3574,7 @@ function defineRefPropWarningGetter(props, displayName) {
  * @internal
  */
 
-var ReactElement = function (type, key, ref, self, source, owner, props) {
+function ReactElement(type, key, ref, self, source, owner, props) {
   var element = {
     // This tag allows us to uniquely identify this as a React Element
     $$typeof: REACT_ELEMENT_TYPE,
@@ -3626,7 +3626,7 @@ var ReactElement = function (type, key, ref, self, source, owner, props) {
   }
 
   return element;
-};
+}
 /**
  * https://github.com/reactjs/rfcs/pull/107
  * @param {*} type

compiled/facebook-www/React-dev.modern.js

@@ -27,7 +27,7 @@ if (
 }
           "use strict";
 
-var ReactVersion = "18.3.0-www-modern-724bb919";
+var ReactVersion = "18.3.0-www-modern-9bafe2f6";
 
 // ATTENTION
 // When adding new symbols to this file,
@@ -756,7 +756,7 @@ function warnIfStringRefCannotBeAutoConverted$1(config) {
  * @internal
  */
 
-var ReactElement$1 = function (type, key, ref, self, source, owner, props) {
+function ReactElement$1(type, key, ref, self, source, owner, props) {
   var element = {
     // This tag allows us to uniquely identify this as a React Element
     $$typeof: REACT_ELEMENT_TYPE,
@@ -808,7 +808,7 @@ var ReactElement$1 = function (type, key, ref, self, source, owner, props) {
   }
 
   return element;
-};
+}
 /**
  * Create and return a new ReactElement of the given type.
  * See https://reactjs.org/docs/react-api.html#createelement
@@ -3539,7 +3539,7 @@ function defineRefPropWarningGetter(props, displayName) {
  * @internal
  */
 
-var ReactElement = function (type, key, ref, self, source, owner, props) {
+function ReactElement(type, key, ref, self, source, owner, props) {
   var element = {
     // This tag allows us to uniquely identify this as a React Element
     $$typeof: REACT_ELEMENT_TYPE,
@@ -3591,7 +3591,7 @@ var ReactElement = function (type, key, ref, self, source, owner, props) {
   }
 
   return element;
-};
+}
 /**
  * https://github.com/reactjs/rfcs/pull/107
  * @param {*} type

compiled/facebook-www/ReactART-dev.classic.js

@@ -69,7 +69,7 @@ function _assertThisInitialized(self) {
   return self;
 }
 
-var ReactVersion = "18.3.0-www-classic-5ea6b0b1";
+var ReactVersion = "18.3.0-www-classic-d10ee72f";
 
 var LegacyRoot = 0;
 var ConcurrentRoot = 1;
@@ -10978,11 +10978,10 @@ var didWarnAboutUninitializedState;
 var didWarnAboutGetSnapshotBeforeUpdateWithoutDidUpdate;
 var didWarnAboutLegacyLifecyclesAndDerivedState;
 var didWarnAboutUndefinedDerivedState;
-var warnOnUndefinedDerivedState;
-var warnOnInvalidCallback;
 var didWarnAboutDirectlyAssigningPropsToState;
 var didWarnAboutContextTypeAndContextTypes;
 var didWarnAboutInvalidateContextType;
+var didWarnOnInvalidCallback;
 
 {
   didWarnAboutStateAssignmentForComponent = new Set();
@@ -10993,9 +10992,30 @@ var didWarnAboutInvalidateContextType;
   didWarnAboutUndefinedDerivedState = new Set();
   didWarnAboutContextTypeAndContextTypes = new Set();
   didWarnAboutInvalidateContextType = new Set();
-  var didWarnOnInvalidCallback = new Set();
+  didWarnOnInvalidCallback = new Set(); // This is so gross but it's at least non-critical and can be removed if
+  // it causes problems. This is meant to give a nicer error message for
+  // ReactDOM15.unstable_renderSubtreeIntoContainer(reactDOM16Component,
+  // ...)) which otherwise throws a "_processChildContext is not a function"
+  // exception.
+
+  Object.defineProperty(fakeInternalInstance, "_processChildContext", {
+    enumerable: false,
+    value: function () {
+      throw new Error(
+        "_processChildContext is not available in React 16+. This likely " +
+          "means you have multiple copies of React and are attempting to nest " +
+          "a React 15 tree inside a React 16 tree using " +
+          "unstable_renderSubtreeIntoContainer, which isn't supported. Try " +
+          "to make sure you have only one copy of React (and ideally, switch " +
+          "to ReactDOM.createPortal)."
+      );
+    }
+  });
+  Object.freeze(fakeInternalInstance);
+}
 
-  warnOnInvalidCallback = function (callback, callerName) {
+function warnOnInvalidCallback(callback, callerName) {
+  {
     if (callback === null || typeof callback === "function") {
       return;
     }
@@ -11012,9 +11032,11 @@ var didWarnAboutInvalidateContextType;
         callback
       );
     }
-  };
+  }
+}
 
-  warnOnUndefinedDerivedState = function (type, partialState) {
+function warnOnUndefinedDerivedState(type, partialState) {
+  {
     if (partialState === undefined) {
       var componentName = getComponentNameFromType(type) || "Component";
 
@@ -11028,26 +11050,7 @@ var didWarnAboutInvalidateContextType;
         );
       }
     }
-  }; // This is so gross but it's at least non-critical and can be removed if
-  // it causes problems. This is meant to give a nicer error message for
-  // ReactDOM15.unstable_renderSubtreeIntoContainer(reactDOM16Component,
-  // ...)) which otherwise throws a "_processChildContext is not a function"
-  // exception.
-
-  Object.defineProperty(fakeInternalInstance, "_processChildContext", {
-    enumerable: false,
-    value: function () {
-      throw new Error(
-        "_processChildContext is not available in React 16+. This likely " +
-          "means you have multiple copies of React and are attempting to nest " +
-          "a React 15 tree inside a React 16 tree using " +
-          "unstable_renderSubtreeIntoContainer, which isn't supported. Try " +
-          "to make sure you have only one copy of React (and ideally, switch " +
-          "to ReactDOM.createPortal)."
-      );
-    }
-  });
-  Object.freeze(fakeInternalInstance);
+  }
 }
 
 function applyDerivedStateFromProps(
@@ -18854,20 +18857,10 @@ if (typeof ReactFbErrorUtils.invokeGuardedCallback !== "function") {
   );
 }
 
-var invokeGuardedCallbackImpl = function (
-  name,
-  func,
-  context,
-  a,
-  b,
-  c,
-  d,
-  e,
-  f
-) {
+function invokeGuardedCallbackImpl(name, func, context, a, b, c, d, e, f) {
   // This will call `this.onError(err)` if an error was caught.
   ReactFbErrorUtils.invokeGuardedCallback.apply(this, arguments);
-};
+}
 
 var hasError = false;
 var caughtError = null; // Used by event system to capture/rethrow the first error.
@@ -18949,7 +18942,7 @@ function reportUncaughtErrorInDEV(error) {
   }
 }
 
-var callComponentWillUnmountWithTimer = function (current, instance) {
+function callComponentWillUnmountWithTimer(current, instance) {
   instance.props = current.memoizedProps;
   instance.state = current.memoizedState;
 
@@ -18963,7 +18956,7 @@ var callComponentWillUnmountWithTimer = function (current, instance) {
   } else {
     instance.componentWillUnmount();
   }
-}; // Capture errors so they don't interrupt unmounting.
+} // Capture errors so they don't interrupt unmounting.
 
 function safelyCallComponentWillUnmount(
   current,
@@ -26923,10 +26916,10 @@ function FiberNode(tag, pendingProps, key, mode) {
 // 5) It should be easy to port this to a C struct and keep a C implementation
 //    compatible.
 
-var createFiber = function (tag, pendingProps, key, mode) {
+function createFiber(tag, pendingProps, key, mode) {
   // $FlowFixMe: the shapes are exact here but Flow doesn't like constructors
   return new FiberNode(tag, pendingProps, key, mode);
-};
+}
 
 function shouldConstruct(Component) {
   var prototype = Component.prototype;