worker thread creates could cause mysterious exceptions in
*later* tests (when running all the tests, they appeared
to come out of checkDetail, which runs right after
checkMinimizeTerminates).  Changed the CantRidOfMe class
so that instances of the class *can* be gotten rid of,
keying off a new module bool.  The checkMinimizeTerminates
worker thread uses this to defang the objects after the
body of the test has completed.