81829 Revert “Migrate to ChannelBuffers.push” (a: tests, team, framework, f: material design, a: accessibility, cla: yes, f: cupertino, d: examples)

81843 delete skipped roll_dev_integration_test (team, cla: yes, waiting for tree to go green)

81859 remove unnecessary String.toString() (a: tests, team, tool, framework, f: material design, cla: yes, waiting for tree to go green)

81865 Add Enter and Tab back in to ios and macos key maps (team, framework, cla: yes)

81869 Update perf_tests.dart (team, cla: yes)

81873 Sort imports when interpolating sample templates (team, cla: yes, waiting for tree to go green)