[co19] Enables slow tests on dartdevk and dartdevc
[co19] Enables slow tests on dartdevk and dartdevc

Change-Id: Id44d372ed90c54523c9dde4659b4776923dfcadf
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/196488
Reviewed-by: Erik Ernst <251bb01623bfda2cd9151e339a6e783ca432874c@google.com>
Reviewed-by: Alexander Thomas <29642742b6693024c89de8232f2e2542cf7eedf7@google.com>
Commit-Queue: Erik Ernst <251bb01623bfda2cd9151e339a6e783ca432874c@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk