31622 refactor context to be implicit-downcast safe (cla: yes)

31623 fix edge swiping and dropping back at starting point (cla: yes, f: cupertino, framework)

31634 Improve canvas example in sample dart ui app (cla: yes, d: api docs, d: examples, framework)

31638 Fix doc link (cla: yes)

31642 Refactor the test compiler into a separate library (cla: yes)

31687 Center iOS caret, remove constant offsets that do not scale (a: text input, cla: yes, framework, ⌺‬ platform-ios)

31692 Revert “Add support for Tooltip hover (#31561)” (cla: yes)