Ignore OOMEs in ThreadStress' QueuedWait operation.

Previous work on ThreadStress' QueuedWait operation avoided some
out-of-memory issues by by forcing ahead-of-time initialization of
classes used by the Semaphore class (see
https://android-review.googlesource.com/508595).
However, the execution of code from the Semaphore can still throw an
OutOfMemoryError as some of its code paths allocate memory. In that
case (which is expected to be rare), just ignore the OOME and continue
the execution.

Test: art/test/testrunner/testrunner.py -t 004-ThreadStress
Bug: 71570713
Change-Id: I0970e9cc768ce69c669ed75ade22961700ed4549