[clang] [Clang] Fix 'counted_by' for nested struct pointers (PR #110437)

[Bill Wendling via cfe-commits]

bwendling wrote:

Thanks for this, but I think the issue is more basic. We should be issuing a "load" instruction after the `EmitMemberExpr` call. (That's what happens outside of using this in `__builtin_dynamic_object_size`.)

https://github.com/llvm/llvm-project/pull/110437