[llvm] [InstCombine] Extend `foldICmpAddConstant` to disjoint `or`. (PR #75899)

[Mikhail Gudim via llvm-commits]

mgudim wrote:

> Reverse ping :)

I am busy working on other things now, but I plan to come back to this.

https://github.com/llvm/llvm-project/pull/75899