deaa600204
Trying to reland #140115 which I had to revert in #142889 because [it broke the tree](https://github.com/flutter/flutter/pull/140115#issuecomment-1925774719). In this PR I fixed the post-submit following tests:
Tracing tests
"Application"
The lib/test.dart and lib/control.dart files in this directory are
used by dev/bots/test.dart's runTracingTests function to check
whether aspects of the tracing logic in the framework get compiled out
in profile and release builds. They're not meant to be run directly.
The strings in these files are used in dev/bots/test.dart.
Tests
The tests in this folder must be run with flutter test --enable-vmservice,
since they test that trace data is written to the timeline by connecting to
the observatory.
These tests will fail if run without this flag.