[clang] [Clang-REPL] Fix crash during `__run_exit_handlers` with dynamic libraries. (PR #117475)

[via cfe-commits]

SahilPatidar wrote:

I have added a test, but it should only run on Darwin (macOS) platforms.
```cpp
// REQUIRES: host-supports-jit

// RUN: cat %s | env SDKROOT=$(xcrun --show-sdk-path) DYLD_LIBRARY_PATH=%S/Inputs:$DYLD_LIBRARY_PATH clang-repl

%lib vec.dylib
#include <vector>
std::vector<int> v;
%quit

```

https://github.com/llvm/llvm-project/pull/117475