[clang] [Clang] Disable use of the counted_by attribute for whole struct pointers (PR #112636)

[Jan Hendrik Farr via cfe-commits]

Cydox wrote:

I was forgetting about the padding when thinking about this part of the quote:
> it behaves as if that member were replaced with the longest array (with the same element type) that would not make **the structure** larger than the object being accessed

https://github.com/llvm/llvm-project/pull/112636