Revert "Roll src/third_party/dart be66176534..f4229da6ab (29 commits)" (#12029)

This reverts commit 0f492d8a.

DEPS

@@ -34,7 +34,7 @@ vars = {
   # Dart is: https://github.com/dart-lang/sdk/blob/master/DEPS.
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': 'f4229da6ab73c9041261df658d8b8874689f87fe',
+  'dart_revision': 'be661765345f62fa4212b76f897fdd3e66e8aa54',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py

ci/licenses_golden/licenses_third_party

-Signature: cc6abe52509f7875a69d648023c1dbad
+Signature: 2c668a8ae65b5189de71c2e56979e785
 
 UNUSED LICENSES:
 
@@ -7446,8 +7446,6 @@ FILE: ../../../third_party/dart/runtime/tools/dartfuzz/gen_api_table.dart
 FILE: ../../../third_party/dart/runtime/tools/graphexplorer/graphexplorer.html
 FILE: ../../../third_party/dart/runtime/tools/graphexplorer/graphexplorer.js
 FILE: ../../../third_party/dart/runtime/tools/run_clang_tidy.dart
-FILE: ../../../third_party/dart/runtime/vm/bss_relocs.cc
-FILE: ../../../third_party/dart/runtime/vm/bss_relocs.h
 FILE: ../../../third_party/dart/runtime/vm/catch_entry_moves_test.cc
 FILE: ../../../third_party/dart/runtime/vm/class_id.h
 FILE: ../../../third_party/dart/runtime/vm/code_comments.cc