[llvm] Rework i1->i32 zext/anyext translation (PR #114721)

[Jay Foad via llvm-commits]

https://github.com/jayfoad commented:

This is a tricky area to get right. I don't think your patch should be merged as-is because it seems to cause a lot of code quality regressions. I've called out some of them inline, but there are plenty more if you look through the diffs.

https://github.com/llvm/llvm-project/pull/114721