[infra] Skip all co19_2 tests that are timing out on dartdevc.
[infra] Skip all co19_2 tests that are timing out on dartdevc.

The deflaking phase of testing is breaking when trying to handle
too many timing-out tests at once, stopping the builder runs.
Skipping them until we can debug the problem.

Change-Id: Id3243d8123465ca119262028dfe04d18d41b48c6
Reviewed-on: https://dart-review.googlesource.com/c/92139
Reviewed-by: Vijay Menon <671ecbb18d31a1c038875027dcfe976af959ea9f@google.com>

dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk