[MS Demangler] Better demangling of template arguments.

This patch fixes demangling of template aliases as template-template
arguments, and also fixes function pointers and references as
not type template parameters.  All of these can be properly
demangled now, so I've ported over the test
clang/test/CodeGenCXX/ms-template-callbacks.cpp.  All of these
tests pass

llvm-svn: 338340