[bug][clang][windows] clang-cl 22 stack overflow when using multi-level `std::throw_with_nested`

## Summary

Multi-level nested exceptions (2+ levels of `std::throw_with_nested`) with clang-cl 22 on Windows (MSVC STL) causes infinite recursion and stack overflow.
This also happens when using clang (not clang-cl).

## Environment

- **Clang Version**: 22.1.3 (targeting x86_64-pc-windows-msvc)
- **MSVC Runtime**: Tested with 14.44.35211.0 and 14.50.35719.0 (both fail)
- **OS**: Windows 11 Enterprise Build 26100
- **Compiler Flags**:
- `/EHsc` (Exceptions enabled)

## Reproduction

Single-level nesting: ✅ WORKS
Double-level nesting: ❌ CRASHES

### Minimal Test Case

```cpp
#include
#include
#include

int
main()
{
try
{
try
{
try
{
throw std::exception();
}
catch (...)
{
std::throw_with_nested(std::exception());
}
}
catch (...)
{
std::throw_with_nested(std::exception());
}
}
catch (...)
{
auto ptr = std::current_exception();
std::cout << "Retrieved exception pointer from current_exception().\n";
}
return 0;
}
```

### Compile Command

```bash
clang-cl /EHsc test.cpp
```

### Expected Behavior

Program should catch the nested exception and print `Retrieved exception pointer from current_exception().`

### Actual Behavior

Infinite recursion in exception handling, stack overflow after a lot of frames:

```raw
* thread #1, stop reason = Exception 0xc0000005 encountered at address 0x7ffb9e910a24: Access violation writing location 0xdf86e00f88
* frame #0: 0x00007ffb9e910a24 ntdll.dll`RtlSetBits + 3604
frame #1: 0x00007ffb9e8dd151 ntdll.dll`RtlAllocateHeap + 3841
frame #2: 0x00007ffb9e8dcd24 ntdll.dll`RtlAllocateHeap + 2772
frame #3: 0x00007ffb9e910388 ntdll.dll`RtlSetBits + 1912
frame #4: 0x00007ffb9e912e5a ntdll.dll`RtlSetBits + 12874
frame #5: 0x00007ffb9e8dd151 ntdll.dll`RtlAllocateHeap + 3841
frame #6: 0x00007ffb9e8dcd24 ntdll.dll`RtlAllocateHeap + 2772
frame #7: 0x00007ff7b7aa31e4 test.exe`
frame #8: 0x00007ff7b7a99b2d test.exe`
frame #9: 0x00007ff7b7a912aa test.exe`
frame #10: 0x00007ff7b7a91242 test.exe`
[goes infinite from here...]
frame #14046: 0x00007ff7b7aa05c7 test.exe`
frame #14047: 0x00007ffb9e9e1386 ntdll.dll`RtlCaptureContext2 + 1190
frame #14048: 0x00007ff7b7a91043 test.exe`
frame #14049: 0x00007ff7b7a987cc test.exe`
frame #14050: 0x00007ffb9d44e8d7 kernel32.dll`BaseThreadInitThunk + 23
frame #14051: 0x00007ffb9e94c48c ntdll.dll`RtlUserThreadStart + 44
```

Start with the minimal reproduction in test.cpp and run it with clang-cl /EHsc on Windows using the reported Clang and MSVC runtime versions. Compare single-level and multi-level std::throw_with_nested behavior; done means the multi-level case catches the nested exception, prints the expected message, and no longer recurses until stack overflow.

Written by the indexing model from the issue text.