http2: simplify onSelectPadding

`OnCallbackPadding` on the native side already clamps
the return value into the right range, so there’s not need
to also do that on the JS side.

Also, use `>>> 0` instead of `| 0` to get an uint32, since
the communication with C++ land happens through an Uint32Array.

PR-URL: #17717
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/internal/http2/core.js

@@ -353,11 +353,7 @@ function onSelectPadding(fn) {
   return function getPadding() {
     const frameLen = paddingBuffer[PADDING_BUF_FRAME_LENGTH];
     const maxFramePayloadLen = paddingBuffer[PADDING_BUF_MAX_PAYLOAD_LENGTH];
-    paddingBuffer[PADDING_BUF_RETURN_VALUE] =
-        Math.min(maxFramePayloadLen,
-                 Math.max(frameLen,
-                          fn(frameLen,
-                             maxFramePayloadLen) | 0));
+    paddingBuffer[PADDING_BUF_RETURN_VALUE] = fn(frameLen, maxFramePayloadLen);
   };
 }