Expose _PyEval_StopTheWorld and _PyEval_StartTheWorld as unstable API #137219
Description
Profilers and debuggers need some syncronization points to inspect the stack of all the threads when activated to establish a baseline. In the free threaded build this cannot be done currently as other threads are running and the procedure is racy without being able to stop everything. We do have private APIs for this but they are not exposed and without them these tools cannot add proper free threaded support.