[llvm] [IR] Avoid call to deprecated PointerType::get (NFC) (PR #134609)

[Sven van Haastregt via llvm-commits]

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

Thanks, this fixes the warnings on e.g. gcc 9.4 too.

https://github.com/llvm/llvm-project/pull/134609