[MS ABI] Assign an inheritance model for the dest of a member pointer upcast

While we correctly assigned an inheritance model for the source of a
member pointer upcast, we did not do so for the destination.

This fixes PR27030.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@264065 91177308-0d34-0410-b5e6-96231b3b80d8