[ms-inline asm] Add support for operands that include both a symbol and an
immediate displacement.  Specifically, add support for generating the proper IR.
We've been able to parse this for some time now.  Test case to be added on the
clang side.
Part of rdar://13453209


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179393 91177308-0d34-0410-b5e6-96231b3b80d8