[clang] [clang] Exclude EmptyRecord when calculating larger CXX records (PR #205040)

[Phoebe Wang via cfe-commits]

phoebewang wrote:

> Needs release note.

Done.

> Do we we want to support `-fclang-abi-compat=22` for this?

I think not. 1) It is a transient bug lives in 21 and 22 only; 2) It may confuse users given the behavior back and forth.

https://github.com/llvm/llvm-project/pull/205040