[-cxx-abi microsoft] Mangle member pointers better

Summary:
There were several things going wrong:
- We mangled in useless qualifiers like "volatile void" return types.
- We didn't propagate 64-bit pointer markers sufficiently.
- We mangled qualifiers belonging to the pointee incorrectly.

This fixes PR16844 and PR16848.

Reviewers: rnk, whunt

Reviewed By: rnk

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1353