[clang] [Serialization] Check for stack exhaustion when reading declarations (PR #79875)

[Ilya Biryukov via cfe-commits]

https://github.com/ilya-biryukov commented:

I think the alternative we could try to chase is turning the chain of using-shadow-decls into an array somehow, so we can process it in a loop instead of recursion.

I am not sure if there is an an approach that does **not** involve structural changes to the AST (i.e. rewriting the `ASTReaderDecl` somehow, but keeping the AST the same). Maybe someone more experienced with the serialization could suggest something useful here, that would probably be ideal.

https://github.com/llvm/llvm-project/pull/79875