29599 Call Dart messenger methods in DartExecutor (platform-android, cla: yes, waiting for tree to go green, needs tests)

29620 Check for both compose string and result string. (cla: yes, platform-windows, needs tests)

29621 Fix UB in semantics updates (cla: yes, needs tests, embedder)

29622 [web] Fix warning about the non-nullable flag (cla: yes, waiting for tree to go green, platform-web, needs tests)

29632 [fuchsia] Move TODOs for Dart v2 to specific bugs. (cla: yes, platform-fuchsia, needs tests)

29633 Exit with failure code if clang-tidy finds linter issues (cla: yes, waiting for tree to go green, needs tests)