llvm/test/CodeGen/X86/shift-pcmp.ll: Tweak to appease FileCheck. "CHECK-LABEL"...

llvm/test/CodeGen/X86/shift-pcmp.ll: Tweak to appease FileCheck. "CHECK-LABEL" doesn't identify labels magically and CHECK-LABEL behaves free from other contexts.

For targeting pecoff, ".def foo" appears before ".short 32".

          .def    foo;
  ...
  .LCPI0_0:
          .short  32
  foo:

CHECK-LABEL seeks not from ".short 32" but from the top of the input.

llvm-svn: 201931