Enable web tool integration tests: expression evaluation, stepping, and basic hot restart

Enables build_test for Linux. Currently only flutter_gallery has platform directories for the desktop platforms, so this will run only that build, but this will provide an end-to-end build test for Linux.

Other example/test projects can be brought online for Linux in the future just by adding the linux/ directory to the project.

* [devicelab] work around occasional null values for devtools

* Update perf_tests.dart

This reverts commit d0cdfa41.

Currently we only have a test that measures if flutter drive can fail. Unfortunately it has been failing for multiple years based on the fact that the error is due to a missing Gradle config.

Add a smoke success test case, and update both tests to use the test API and the tester-device.

073263e39 Roll Skia from 5bbbb49f1da0 to 7737a5bd2510 (13 revisions) (flutter/engine#22140) (#69231)

Support --web-renderer options which would allow user to specify which rendering backend to use. (#68848)

[flutter_tools] conditionally invoke pub run test for drive scripts based on presence of dependency (#69246)

* [flutter_tools] conditionally invoke pub run test for drive scripts based on presence of dependency

* [flutter_tools] stage web integration tests

* Improve resampling of up and remove events.

This improves resampling of these events by searching
for them until the next approximate sample time.
Co-authored-by: David Reveman <reveman@google.com>

(Reland) Fixes a bug where keyboard capitalization behavior was reset by TextEditingController.clear.

* [flutter_tools] use throwToolExit

* Update drive.dart

Fixes a bug where selection handles sometimes showed on web.

Add side property to Chips, and resolve it and the state of Chips to be MaterialState aware (#68596)

Adds MediaQuery.maybeOf to replace calling MediaQuery.of(context, nullOk: true), and removes the nullOk parameter. Also changes MediaQuery.of to return a non-nullable value, and removes many instances of the ! operator, reducing the possible places where a null dereference could occur.