[MS Demangler] Add conversion operator tests.

The mangled names were added in the original commit, but
the demangled equivalents weren't, so nothing was actually
being checked.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339450 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed