One test (deadlock detection) generates an inordinate number of
threads (~150).  Problematically, the test does not clean up a number
of these threads itself, meaning that they stick around for the
lifetime of running all tests.  On some machines, this can lead to
an error where the os refuses to allocate any more threads to Waldo.
To deal with this, decided to run deadlock detection test in a
separate process.  When the process closes, will automatically return
and recycle available threads.