[ms-inline asm] Remove the brackets from X86Operand in the IR. These will be

added back in by X86AsmPrinter::printIntelMemReference() during codegen.
Previously, this following example

  void t() {
    int i;
    __asm mov eax, [i]
  }

would generate the below assembly

  mov eax, dword ptr [[eax]]

which resulted in a fatal error when compiling.  Test case coming on the
clang side.
rdar://13444264

llvm-svn: 177440