[clang] [clang][CodeGen] Make `UnqualPtrTy` truly unqualified (PR #94388)

[Alex Voicu via cfe-commits]

https://github.com/AlexVlx commented:

> I don't think that assumption is currently true. I think it's also worth clarifying what this thing is, and possibly renaming it, because "unqualified" has C language level meaning that would contradict what it is here. 

It's probably optimistic, based on us also having `Int8PtrTy` / `VoidPtrTy` which seem less "scary" (for lack of a better word) and more familiar for someone coming from e.g. C. In what regards renaming, I don't have an immediate idea of what to rename it too, and it's tied to `PointerType::getUnqual`, so if we rename this we'd probably have to rename that as well, no?

https://github.com/llvm/llvm-project/pull/94388