[X86] Canonicalize SGT/UGT compares with constants to use SGE/UGE to reduce...

[X86] Canonicalize SGT/UGT compares with constants to use SGE/UGE to reduce the number of EFLAGs reads. (PR48760)

This demonstrates a possible fix for PR48760 - for compares with constants, canonicalize the SGT/UGT condition code to use SGE/UGE which should reduce the number of EFLAGs bits we need to read.

As discussed on PR48760, some EFLAG bits are treated independently which can require additional uops to merge together for certain CMOVcc/SETcc/etc. modes.

I've limited this to cases where the constant increment doesn't result in a larger encoding or additional i64 constant materializations.

Differential Revision: https://reviews.llvm.org/D101074