86837 [flutter] remove elevation checker (tool, framework, cla: yes, waiting for tree to go green)

86877 Remove default expectation for UserTag (framework, cla: yes, waiting for tree to go green, will affect goldens)

86896 refactor the widget rebuild service protocol event format (framework, cla: yes)

86910 Added Checkbox support for MaterialStateBorderSide (framework, f: material design, cla: yes)

86912 Reland 2: Make LiveTestWidgetsFlutterBinding work with setSurfaceSize and live tests (a: tests, framework, cla: yes, waiting for tree to go green, will affect goldens)

86960 Only stop search for upstream character if we hit a newline (framework, cla: yes)