[clang] [CIR] Implement cir.cmp3way Operation (PR #186294)

[Yeongu Choe via cfe-commits]

YeonguChoe wrote:

@HendrikHuebner 

It's alright. I learned new things while making the codes.
I hope your code merges well.

https://github.com/llvm/llvm-project/pull/186294