Includes the Engine roll from
https://github.com/flutter/flutter/pull/141841

A new version of Dart is having trouble with the tool integration test
test `passing one file with errors are detected`:
https://ci.chromium.org/ui/p/flutter/builders/try/Mac%20tool_integration_tests_2_4/31851/overview.

However the analysis server emits the expected errors when we give it
both the file without issues and the file with issues.

My guess is that the analysis server has changed it's behavior slightly
when supplied with a single malformed file.

Since the Dart roll is >20 dev versions behind, and this is the only
failing presubmit test, and it's testing something a bit weird, I
suggest we investigate the right way to test the thing that test was
attempting to cover as a follow-up.