[ms-inline asm] Create a helper function, CreateMemForInlineAsm, that creates

[ms-inline asm] Create a helper function, CreateMemForInlineAsm, that creates
an X86Operand, but also performs a Sema lookup and adds the sizing directive
when appropriate.  Use this when parsing a bracketed statement.  This is
necessary to get the instruction matching correct as well.  Test case coming
on clang side.
rdar://13455408

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177439 91177308-0d34-0410-b5e6-96231b3b80d8