[clang] [TBAA] Don't emit pointer-tbaa for void pointers. (PR #122116)

[John McCall via cfe-commits]

rjmccall wrote:

I agree that allowing `void*` l-values to alias arbitrary pointer objects is probably the right pragmatic choice. We should document it, though.

@pinskia, does GCC apply this recursively — e.g. are `void**` l-values treated specially in any way, or are they basically just `char**` for aliasing purposes?

https://github.com/llvm/llvm-project/pull/122116