[inline asm] Add a test case for r180226.  The specific issue is that the inline
assembly is requesting a 64-bit register, which is invalid for i386.
rdar://13731657


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180445 91177308-0d34-0410-b5e6-96231b3b80d8