Add AddressSpace mangling to MS mode

All of the symbols demangle on llvm-undname and demangler.com. This
address space qualifier is useful for when we want to use opencl C++ in
Windows mode. Additionally, C++ address-space using functions will now
be usable on windows.

Differential Revision: https://reviews.llvm.org/D55715

Change-Id: Ife4506613c3cce778a783456d62117fbf7d83c26
llvm-svn: 349209