This reverts commit 275ab9c6.

Revert "Reland "Remove references to Observatory (#118577)""

This reverts commit 298d8c76.

This reverts commit 2df140f4.

Observatory is being deprecated for Dart 3.0 so it should no longer be
referenced in tooling messaging / flags.

See https://github.com/dart-lang/sdk/issues/50233

This reverts commit 53e68762.

* allow marking a golden check as flaky

* add matchesFlutterGolden to analyze.dart; no tags for flutter_goldens/lib

* Pause

* ++

* ++

* Analyzer therapy

* Once more with feeling

* Nits

* Review feedback

* Silly oops

* Test progress

* More tests

* Finish

* Nits

* Analyzer

* Review feedback
Co-authored-by: Yegor Jbanov <yjbanov@google.com>

This reverts commit 027d4eca.

Revert "[flutter_tools] remove mocks, globals from golden comparator and test runner tests (#81423)" (#81487)

This reverts commit 8fe4cc79.

This reverts commit 8b6baae4.

Our current top crasher is an unclear error when ProcessManager fails to resolve an executable path. To fix this, we'd like to being adjusting the process resolution logic and adding more instrumentation to track failures. In order to begin the process, the ProcessManager has been folded back into the flutter tool

* opt out the flutter tool

* oops EOF

* fix import

* Update tool_backend.dart

* Update daemon_client.dart

* fix more

Last batch of test fixes for general shard.