[clang] [C++20][Modules] Fix crash when function and lambda inside loaded from different modules (PR #109167)

[Dmitry Polukhin via cfe-commits]

dmpolukhin wrote:

> still trying to reduce the reproducer...

Please create a reproducer, the stack trace doesn't have information to understand what is causing the issue.

https://github.com/llvm/llvm-project/pull/109167