Note on BC and type assertions

[Tom Tromey]

While browsing the verifier again, I noticed that there is a dynamic
constraint that we can't represent using our current type
assertions, namely:

	    if (type_isarray (&t) || type_isinterface (&t) \
		|| type_isabstract (&t))
	      verify_fail ("type is array, interface, or abstract");

We could put this check in _Jv_AllocObject (the worst option IMO), add
a new kind of verification assertion, or write a BC-only wrapper for
_Jv_AllocObject that does this check.

There may be other assertion types we need to handle as well, a pass
through the verifier looking for them is warranted.

Tom