[InstSimplify] [NFC] cast-unsigned-icmp-cmp-0.ll - don't run instcombine

As disscussed in post-commit review of D44421, there is simply
no reason to run instcombine on this testcase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327541 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed