[X86] X86FixupVectorConstantsPass - attempt to match VEX logic ops back to...

[X86] X86FixupVectorConstantsPass - attempt to match VEX logic ops back to EVEX if we can create a broadcast fold

On non-DQI AVX512 targets, X86InstrInfo::setExecutionDomainCustom will convert EVEX int-domain instructions to VEX fp-domain instructions. But, if we have the chance to use a broadcast fold we're better off using a EVEX instruction, so handle a reverse fold.