[clang] [clang-repl] Keep the first llvm::Module empty to avoid invalid memory access. (PR #89031)

[Lang Hames via cfe-commits]

https://github.com/lhames approved this pull request.

If there's a trivial reproducer for the original issue it may be worth adding it as a regression test.

https://github.com/llvm/llvm-project/pull/89031