.8.2.21

.8.2.21
	Fixes for a couple of threading bugs found by Gilbert Baumann

	... CONDITION-WAIT should acquire the lock with the correct
	    value (i.e. the one it had when it went to sleep), not
	    just the default value.
	... CONDITION-NOTIFY should get the queue spinlock before
	    signalling, making it atomic wrt WAIT-ON-QUEUE

	Added rudimentary thread test script that I thought I'd
	committed on some previous occasion