[gardening] Skip flaky lib_2/async/stream_state_nonzero_timer_test
[gardening] Skip flaky lib_2/async/stream_state_nonzero_timer_test

This test sporadically crashes and confuses
vm-dartkb-linux-release-x64-abi bot which compares results on different
versions of ABI.

Issue: https://github.com/dart-lang/sdk/issues/42073
Issue: https://github.com/dart-lang/sdk/issues/42331
Change-Id: Ib61ca37ed07f40384f78e19e40c51096dd68dc08
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/152591
Reviewed-by: Liam Appelbe <78c2029e58e395825ba7228e218c841bb436a9e9@google.com>
Commit-Queue: Alexander Markov <239e774fd29abc1267878f57afe1a8a03e0ca887@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