[x86] remove dead select-of-constants transform; NFCI

https://reviews.llvm.org/D30537 / https://reviews.llvm.org/rL296977 added these transforms
and other related transforms to the generic DAGCombiner (with a hook that x86 sets to true),
so these patterns should not exist by the time we reach the target-specific combiner hook.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299448 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed