[InstCombine] fix test to restore intent

[InstCombine] fix test to restore intent

This test had values that differed in only in capitalization,
and that causes problems for the auto-generating check line
script. So I changed that in rL331226, but I accidentally
forgot to change a subsequent use of a param.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331228 91177308-0d34-0410-b5e6-96231b3b80d8