Hang in RandomProgramTraceFixture gtests with async dipatch out of ethernet on BH

[abhullar-tt]

Trace test fixture exposes this issue but it doesn't seem related to Trace because hang is seen even without Tracing (just back to back EnqueueProgram). This fixture might be exposing issues because many programs are running back to back.

Hang goes away when async dispatch is disabled.

Hang signature is similar to WH LLama hang but the barrier workarounds don't alleviate the hang and it is seen even with unicasts.