[X86] Switch the 64-bit mulx schedule test to use inline assembly.

I'm not sure we should always prefer MULX over MUL. So making the MULX guaranteed with inline assembly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348833 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed