[InstCombine] Remove redundant combine from visitAnd

This combine is fully handled by SimplifyDemandedInstructionBits as of r299658 where I fixed this code to ensure the Add/Sub had only a single user. Otherwise it would fire and create additional instructions. That fix resulted in an improvement to code generated for tsan which is why I committed it before deleting.

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

llvm-svn: 299704