25619 [flutter_releases] Flutter Stable 2.0.5 Engine Cherrypicks (platform-android, cla: yes, platform-web, platform-windows, platform-fuchsia)

25653 Start microtasks only in non-test envs (platform-ios, cla: yes, waiting for tree to go green, platform-fuchsia)

25655 Revert “[fuchsia] Use scenic allocator service” (cla: yes, platform-fuchsia)

25663 Revert “[fuchsia] Use scenic allocator service (#25385)” (#25655) (cla: yes, platform-fuchsia)

25690 Revert TaskRunner changes to fix Fuchsia Test failures (platform-ios, cla: yes, platform-fuchsia, embedder)