[llvm] [X86] Fix swapped VPTERNLOG231_imm8/VPTERNLOG312_imm8 SDNodeXForm bodies (PR #209782)

[via llvm-commits]

AntonyCJ30 wrote:

@RKSimon Done! Split into 2 commits as requested:
1. Test changes (regenerated + 4 new cases)
2. Code fix (swap the XForm bodies)

Thanks for the review!

https://github.com/llvm/llvm-project/pull/209782