[clang] [CIR] Lower bitwise vector reduce builtins (PR #201164)

[Erich Keane via cfe-commits]

https://github.com/erichkeane approved this pull request.

I might do the result type override a little differently, but I don't have anything concrete as an idea, so this is probably good enough for now.  Its unfortunate we have to do this, we should think of a way to not have to.

https://github.com/llvm/llvm-project/pull/201164