Reland of #52091

This reverts commit f65421aa.

Remove dependency injection from GenSnapshot and AotBuilder and update tests to use FakeProcessManager

* Do not throw when trying to discover a fuchsia device and the sshConfig is invalid

216c420a2 Roll src/third_party/skia afa83bc20b2c..d3b92b910ce0 (2 commits) (flutter/engine#17201) (#52865)

* 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.

This reverts commit 1f173184.

This is necessary to ensure the tests can run in google3. Fixes https://b.corp.google.com/issues/151657461

TextFields now disallow adding characters in the center of the text at maxLength.