[llvm] [LangRef][IR] Add 3 way compare <=> integer intrinsics (PR #83227)

[Miguel Raz Guzmán Macedo via llvm-commits]

miguelraz wrote:

@nikic Only 2 blockers remaining I think:
1. `intrinsic-cmp.ll` is failing the `llvm-lit` invocation
2. formatting nits


https://github.com/llvm/llvm-project/pull/83227