[clang] [analyzer] Avoid overwriting the default binding of union aggregates in incomplete array initializers (PR #178694)

[Donát Nagy via cfe-commits]

NagyDonat wrote:

Looks reasonable.

Did you try to evaluate this on some open source projects to see whether it introduces any unwanted side effects? (I strongly suspect that there are no side effects, but I'm not completely confident because this is a tricky area in the codebase. By the way if you don't have easy access to a testing environment, I can start a job in our CI.)

https://github.com/llvm/llvm-project/pull/178694