[clang] [CodeGen] Add TBAA struct path info for array members (PR #137719)

[John McCall via cfe-commits]

https://github.com/rjmccall commented:

I'm surprised we need all this. Since we don't distinguish arrays from their elements in TBAA, is it not sufficient to just make sure that array subscript expressions produce an l-value with the same TBAA metadata as their base l-value?

https://github.com/llvm/llvm-project/pull/137719