[llvm] [InstCombine] Remove one-use requirement for add iN (sext i1 X), (sext i1 Y) --> sext (X | Y) to iN (PR #90509)

[via llvm-commits]

AtariDreams wrote:

> Increases instruction count if both sexts have extra uses.

Just checked and at worst the count stays the same.

https://github.com/llvm/llvm-project/pull/90509