75037 [web] benchmark and optimize defaultTargetPlatform (cla: yes, framework, team)

75039 add a benchmark test for stack size (cla: yes, team, waiting for tree to go green)

75044 Replace MockConfig with TestConfig (cla: yes, team, tool, waiting for tree to go green)

75049 Removed the “new” keyword from the Flutter_test examples (a: tests, cla: yes, framework)

75053 Revert “Migrate some benchmarks to NNBD” (cla: yes, team)

75074 Reland integration_test NNBD (a: tests, cla: yes, framework, team)

75095 Fixed improper assertion of maxCrossAxisExtent (cla: yes, f: scrolling, framework)

75096 Grammatical mistake on pull request template (cla: yes, team)