Move to interpreter if async-exceptions are pending.

It was previously possible to miss async exceptions due to a
concurrent exception occurring that allows the thread to enter JITed
code without checking for async-exceptions. Once this happens it is
possible the thread will never re-enter interpreted code where the
exception can be noticed.

Test: ./test.py --host
Test: stress --cpu 60
Bug: 67576489
Change-Id: Ic93490d4b3e945ac92ab9e8c865e07ae76ca213a