0.8.0.23:

0.8.0.23:
	Fix a couple of bugs from Paul Dietz' test suite
	... multiple class/superclass redefinitions can leave a layout
	with an INVALID value of T; this case needs to be handled in
	CHECK-WRAPPER-VALIDITY.  (thanks to Gerd Moellmann)
	... (SETF FIND-CLASS) will eventually pass NIL to (SETF
	FIND-CLASSOID), so that had better be able to handle it.