[InstCombine] add tests for missing icmp + shl nuw fold

Patch by bryant!

Differential Revision: https://reviews.llvm.org/D25952


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285095 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed