0.9.4.54:

0.9.4.54:
	Declassification of INSTANCE and FUNCALLABLE-INSTANCE.

	It turns out that the classes INSTANCE and
        FUNCALLABLE-INSTANCE, as expressed in instance-pointer-lowtag
	and funcallable-instance-widetag, are incompatible with the
	MOP's notion of classes: the types INSTANCE and
	FUNCALLABLE-INSTANCE are necessarily disjoint (no instance can
	have a widetag of anything other than instance-header-widetag),
	but FUNCALLABLE-STANDARD-OBJECT is required to be a subclass of
	STANDARD-OBJECT, and must therefore have the superclasses of
	STANDARD-OBJECT among its superclasses.  If INSTANCE is one of
	those, FUNCALLABLE-INSTANCE cannot be, so F-S-Os would not be of
	type FUNCALLABLE-INSTANCE (which is wrong); if it is not one of
	those, then ordinary S-Os would not be of type INSTANCE (which
	is wrong).  CMUCL, at the time of writing, exhibits type system
	confusion in this area, as demonstrated by CSR cmucl-imp
	2005-09-0x).

	So, we need to do something else; probably most straightforward
	to make INSTANCE and FUNCALLABLE-INSTANCE named types, as they
	are of the same order of specialness as e.g. T -- not quite as
	special, but almost.  Some hacking later...

	... the usual type system dance.  Play whack-a-mole with test
		failures and compilation failures until they all go
		away.  Primtype, class, typetran, and so on are
		fiddled with.
	... somewhat hacky code for determining when a class is subtypep
		instance / funcallable-instance.
	... different hard-coded constants for genesis; don't make a
		special instance-layout, because the instance class is
		gone.
	... just to prove we've achieved something, make STANDARD-OBJECT
		a superclass of FUNCALLABLE-STANDARD-OBJECT.
		(Supporting METAOBJECT should be straightforward now)
	... many many new tests, both of the before-xc variety (it's
		amazing in how many ways I can get the type system
		wrong) and of the regular form.  Also add some
		ctor tests that aren't exercised yet.