[clang] [llvm] Reland "[llvm][ADT] Refactor PointerUnion to use PunnedPointer. NFC." (PR #188242)

[Jakub Kuderski via cfe-commits]

kuhar wrote:

> What do you think about leaving a TODO comment at the very least (both test and code) + an issue and then this can be tackled in a future (non-NFC) PR?

done

https://github.com/llvm/llvm-project/pull/188242