[ms-inline asm] Refactor. No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179610 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unused variable from previous refactor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179611 91177308-0d34-0410-b5e6-96231b3b80d8