[vm] Partially disable 5393ce7d35729e6a6b89e6e9316e99c15a8e3639.
[vm] Partially disable 5393ce7d35729e6a6b89e6e9316e99c15a8e3639.

Avoid flakily failures setting the thread signal mask.

Bug: https://github.com/dart-lang/sdk/issues/36908
Change-Id: I3d66214189f3276365b4c1cc333847cb4f65c94f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/103400
Commit-Queue: Ryan Macnak <d738b7f001baf9789095d7dc549cff6de60b011d@google.com>
Reviewed-by: Alexander Markov <239e774fd29abc1267878f57afe1a8a03e0ca887@google.com>

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