Assume loads fix #2

Assume loads fix #2

There was linker problem, and it turns out that it is not always safe
to refer to vtable. If the vtable is used, then we can refer to it
without any problem, but because we don't know when it will be used or
not, we can only check if vtable is external or it is safe to to emit it
speculativly (when class it doesn't have any inline virtual functions).
It should be fixed in the future.

http://reviews.llvm.org/D12385

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@246214 91177308-0d34-0410-b5e6-96231b3b80d8