Move build web compilers out of workspace

_test/pubspec.yaml

@@ -1,6 +1,9 @@
 name: _test
 publish_to: none
-resolution: workspace
+# This package can't be part of the workspace because it needs to use the local
+# build_web_compilers, which also isn't part of the workspace. See the top-
+# level pubspec for details.
+#resolution: workspace
 
 environment:
   sdk: ^3.6.0-165.0.dev
@@ -24,3 +27,21 @@ dev_dependencies:
     path: pkgs/provides_builder/
   test: ^1.16.0
   test_process: ^2.0.0
+
+dependency_overrides:
+  build:
+    path: ../build
+  build_config:
+    path: ../build_config
+  build_modules:
+    path: ../build_modules
+  build_resolvers:
+    path: ../build_resolvers
+  build_runner:
+    path: ../build_runner
+  build_runner_core:
+    path: ../build_runner_core
+  build_test:
+    path: ../build_test
+  build_web_compilers:
+    path: ../build_web_compilers

build_web_compilers/pubspec.yaml

@@ -2,7 +2,9 @@ name: build_web_compilers
 version: 4.0.12-wip
 description: Builder implementations wrapping the dart2js and DDC compilers.
 repository: https://github.com/dart-lang/build/tree/master/build_web_compilers
-resolution: workspace
+# This package can't be part of the workspace because it requires a very recent
+# Dart SDK - see the top-level pubspec for details.
+#resolution: workspace
 
 environment:
   sdk: ^3.6.0-165.0.dev

pubspec.yaml

@@ -4,8 +4,15 @@ environment:
 publish_to: none
 dev_dependencies:
   dart_flutter_team_lints: ^3.1.0
+
+# build_web_compilers is not currently part of the workspace because it
+# requires a very recent version of the Dart SDK. mono_repo generates a CI
+# definition that runs each package with the lowest SDK version it supports.
+# This breaks `dart pub get` in the entire workspace, so it (and `_test` which
+# needs to use all packages from the repository) can't be part of the
+# workspace.
 workspace:
-- _test
+#- _test
 - _test/pkgs/provides_builder
 - _test_common
 - build
@@ -16,7 +23,7 @@ workspace:
 - build_runner
 - build_runner_core
 - build_test
-- build_web_compilers
+#- build_web_compilers
 - example
 - scratch_space
 - tool