test/CodeGen: Don't rely on a value's number in check lines

The tests in r215568 hard code a value as %0 in their checks. This
isn't correct in asserts builds.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@215585 91177308-0d34-0410-b5e6-96231b3b80d8