84065 Migrate gallery test to null safety (team, a: accessibility, cla: yes, waiting for tree to go green, a: null-safety, tech-debt)

84066 migrate platform channels benchmarks (team, cla: yes, waiting for tree to go green, a: null-safety, tech-debt)

84136 Migrate android_semantics_testing to null safety (team, a: accessibility, cla: yes, waiting for tree to go green, a: null-safety, tech-debt)

84140 Migrate hybrid_android_views to null safety (team, cla: yes, a: null-safety, tech-debt)

84145 Migrate integration_tests/channels to null safety (team, framework, cla: yes, waiting for tree to go green, a: null-safety, tech-debt)