GH-95234 introduced an incorrect condition in the code

In Python/thread.c
```
#elif defined(_POSIX_THREADS)
#   if defined(__EMSCRIPTEN__) || !defined(__EMSCRIPTEN_PTHREADS__)
#     define PYTHREAD_NAME "pthread-stubs"
#   else
#     define PYTHREAD_NAME "pthread"
#   endif
```

|| should be &&.