[llvm] [clang] [NFC] Remove Type::getInt8PtrTy (PR #71029)

[Paulo Matos via cfe-commits]

pmatos wrote:

> I have a similar concern with @arsenm about making the default address space 0. Can't we just use the already existing `PointerType::getUnqual()`, instead of introducing the default address space 0?

True, we could indeed just call `PointerType::getUnqual()` instead of just `PointerType::get()`.

https://github.com/llvm/llvm-project/pull/71029