* Use `curly_braces_in_flow_control_structures` for `material`

* include test/material

* add back removed comments

This reverts commit 5fd259be.

This reverts commit d056500b.

This reverts commit 31de052e.

This reverts commit e2490f29.

updated defualt value of unselectedItemColor textTheme.caption.color to unselectedWidgetColor (#71314)

This migrates more material tests to NNBD.

Updated references to the old button classes to the new ones in comments and documentation for tests in the material and cupertino libraries. (#62164)

* add language version 2.8 in packages/flutter

* enable non-nullable analyzer flag

* Adds default cursor and/or mouseCursor property to a number of widgets.
* Adds `MaterialStateMouseCurrsor`.

* Fix web test flakiness; enable web golden tests

The fix is three-part:

- Only allow one test to load _and_ test at any point in time.
- Use a fresh Chrome instance for each test file.
- Increase Cirrus resources.

The first two changes only fix the "Unknown error loading" error, but not hanging tests. The resource increase also prevents hanging tests.

Other minor changes:

- Remove test batching (it's no longer necessary)
- Fix the Chrome class, which was using the wrong Completer.

Fix tests that rely on FadeTransition incorrectly and depend on implementation details of FadeUpwardsTransitionBuilder (#51150)

[a11y] Make sure RenderFractionalTranslation updates its semantics after the translation field is set (#48985)