[clang] Diagnose problematic uses of constructor/destructor attribute (PR #67360)

[Erich Keane via cfe-commits]

https://github.com/erichkeane approved this pull request.

Do we have a codegen test for the constexpr case?  I'm concerned that we don't 'force' emission of these functions <though, I see they ARE emitted on CE>.

Either way, I think this set of diagnostic changes makes sense.

https://github.com/llvm/llvm-project/pull/67360