* tinfo.h (__user_type_info::contained_virtual_p): New
	predicate.
	* tinfo.cc (__user_type_info::do_upcast): Fix bug with diamond
	shaped heirarchy.
	(__vmi_class_type_info::__do_upcast): Fix bug with NULL pointer to
	diamond shaped heirarchy. Add early out for mixed diamond and
	duplicate shaped heirarchy.

From-SVN: r34163