[InstCombine] Remove redundant combine from visitAnd

As far as I can tell this combine is fully handled by SimplifyDemandedInstructionBits.

I was only looking at this because it is the only user of APIntOps::isShiftedMask which is itself broken. As demonstrated by r299187. I was going to fix isShiftedMask and needed to make sure we had coverage for the new cases it would expose to this combine. But looks like we can nuke it instead.

Differential Revision: https://reviews.llvm.org/D31543

llvm-svn: 299337