add concurrent BPS test
The test introduces multiple cycles of Semaphores and a Fiber for each semaphore blocking and signaling the next. Through work-stealing the fibers from a cycle should be spread across different workers and thus test concurrent use of BinaryPrivateSemaphores.
Cycle of length 3: Sem A -> Sem B -> Sem C -> Sem A -> ...
Algorithm:
if isFirstInCycle
signal next
wait
if not isFirstInCycle
signal next