co19_2 tests failures

[sgrekhov]

Triage failures of co19_2 tests

https://ci.chromium.org/p/dart/builders/ci.sandbox/dart2js-strong-linux-x64-chrome

https://logs.chromium.org/logs/dart/buildbucket/cr-buildbucket/8807646386557525441/+/u/test_results/ignored_flaky_test_failure_logs

[sgrekhov]

All of the failed flaky tests works well for me locally on the edge version of SDK on dart2js-linux-chrome configuration.

[eernstg]

Thanks! I think we can close this, and return to the topic if further concerns are raised.