Fixes https://github.com/flutter/flutter/issues/59413

This relocates `mock_canvas.dart` and `recording_canvas.dart` from `flutter/test/rendering` to `flutter_test`. 

The testing functionality afforded by mock_canvas should be available to everyone, not just the framework. :)

mock_canvas.dart needed a bit of cleanup - things like formatting and super parameters.

Reverts flutter/flutter#131368
Original PR: https://github.com/flutter/flutter/pull/131292 . The
flutter mirror was out of date and tree was closed, so the original PR
was reverted. Now should be safe to have a reland.

Reverts flutter/flutter#131292

This PR is affected by https://g-issues.skia.org/issues/40045533.

See @Piinks's [explanation](https://discord.com/channels/608014603317936148/613398423093116959/1133885989358678076):

> The mirror is probably out of sync. The failing commit introduced new changes, but they have not been updated yet. I would revert the PR until we can check the mirror. Last week it went 2+ hours out of sync so rerunning it may not green the tree for a while.

Updated golden tests in 

* ink_sparkle_test.dart
* material_test.dart
* page_test.dart
* progress_indicator_test.dart

to have M2 and M3 versions.

More info in #127064

* Added support for surfaceTintColor and shadowColor to the Dialog widgets.
* Updated the defaults for Material.shadowColor and Material.surfaceTint to allow turning off the features with a transparent color.
* Added support for shadowColor and surfaceTintColor for Drawer widget.

This reverts commit 5fd259be.

This reverts commit 724c0eb6.

Migrates the following files to NNBD: 
* input_decorator_test.dart
* list_tile_test.dart
* localizations_test.dart
* material_button_test.dart
* material_state_property_test.dart
* material_test.dart
* mergeable_material_test.dart

* Remove opacity from check and add test

Flutter's `moreOrLessEquals` has a few advantages over `closeTo` from
the `matcher` package:

   * It emits the epsilon value in the test result on failure.
   * It uses a named parameter for epsilon, which improves readability
     at the call site.
   * It has a reasonable default for epsilon in cases where something
     more specific isn't required.

Using it also has the nice property that it aids in its own discovery
when when people go looking for such functionality in new tests.

This change also includes a couple unrelated whitespace formatting cleanups.

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