[clang] Fix crash with modules and constexpr destructor (PR #69076)

[Jonas Hahnfeld via cfe-commits]

hahnjo wrote:

Well, this patch is up since almost three months now (!). Sure, we can keep carrying a similar fix downstream, but ideally I would really like to get rid of as many local changes as possible. That's not possible without proper review, but the current situation is quite unsatisfactory...

https://github.com/llvm/llvm-project/pull/69076