29320 Inform the Dart VM when snapshots are safe to use with madvise(DONTNEED). (platform-ios, platform-android, cla: yes, platform-macos, platform-linux, platform-fuchsia)

affects: tests - 7 pull request(s)

27959 Fix StandardMessageCodec test leaks (affects: engine, affects: tests, cla: yes)

28139 fuchsia: Improve FakeSession & add tests (affects: tests, cla: yes, waiting for tree to go green, platform-fuchsia, tech-debt)

28144 fuchsia: Add FuchsiaExternalViewEmbedder tests (affects: tests, cla: yes, platform-fuchsia, tech-debt)