My original patch missed the virtual-base case for destroying

base-class subojects.

Incidentally, thinking about virtual bases makes it clear to me that
we're not appropriately computing the access to the virtual base's
member because we're not computing the best possible access to the
virtual base at all;  in fact, we're basically assuming it's public.
I'll file a separate PR about that.

llvm-svn: 154346