Revert "[ValueTracking] Understand more select patterns in ComputeKnownBits"

This reverts commit r257769. Backing this out because of stage2 failures.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257773 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed