18755 Pin the analyzer version as a temporary workaround for https://github.com/dart-lang/sdk/issues/42163 (cla: yes)

18756 Implement GetAllocationSize for Vertices (cla: yes)

18783 Update 1.17 engine hash to Dart 2.8.4 (cla: yes)

18785 Revert “null-annotate SemanticsUpdateBuilder.updateNode” (cla: yes)

18786 onDisplayPlatformView JNI (cla: yes)

18789 null annotate window.dart (cla: yes)

18790 Removing Flutter for Web firefox tests from cirrus. (cla: yes)

18791 null-annotate semantics.dart (cla: yes)

18792 [web] Adding profile parameter to firefox (cla: yes)