37828 have android_semantics_testing use adb from ENV provided android sdk (a: accessibility, cla: yes, team)

37856 Remove references to solo flag in flutter test (a: tests, cla: yes, d: api docs, framework)

37863 Expose the timeline event names so they can be used in other systems that do tracing (cla: yes, tool)

37870 remove Header flag from BottomNavigationBar items (cla: yes, f: material design, framework, waiting for tree to go green)

37871 Catch failure to create directory in cache (cla: yes, tool)

37872 Unmark devicelab tests as flaky that are no longer flaky (cla: yes, team)

37877 Adds DefaultTextStyle ancestor to Tooltip Overlay (cla: yes, f: material design, framework)