[clang] [analyzer] Wrap SymbolicRegions by ElementRegions before getting a FieldRegion (PR #85211)

[Balazs Benics via cfe-commits]

steakhal wrote:

> I think it's good that we're moving towards establishing the invariant that the parent of a FieldRegion should always be a typed value region (of a suitable type) for the sake of consistency. Do I understand it correctly that this is not too far away? Would it be possible to add an `assert` that mandates this?

I'm not sure. I have not investigated this, and I fear, even if I could run it on a bunch of projects - we could still potentially miss one case where it wouldn't hold. IDK.

https://github.com/llvm/llvm-project/pull/85211