[3.13] gh-137400: Fix a crash when disabling profiling across all threads (gh-137471) (gh-137649)

The `PyEval_SetProfileAllThreads` function and other related functions
had a race condition on `tstate->c_profilefunc` that could lead to a
crash when disable profiling or tracing on all threads while another
thread is starting to profile or trace a a call.

There are still potential crashes when threads exit concurrently with
profiling or tracing be enabled/disabled across all threads.
(cherry picked from commit 362692852f)

Lib/test/test_free_threading/test_monitoring.py

@@ -2,6 +2,7 @@
 environment to verify things are thread-safe in a free-threaded build"""
 
 import sys
+import threading
 import time
 import unittest
 import weakref
@@ -192,6 +193,40 @@ def during_threads(self):
         self.set = not self.set
 
 
+@threading_helper.requires_working_threading()
+class SetProfileAllMultiThreaded(TestCase):
+    def test_profile_all_threads(self):
+        done = threading.Event()
+
+        def func():
+            pass
+
+        def bg_thread():
+            while not done.is_set():
+                func()
+                func()
+                func()
+                func()
+                func()
+
+        def my_profile(frame, event, arg):
+            return None
+
+        bg_threads = []
+        for i in range(10):
+            t = threading.Thread(target=bg_thread)
+            t.start()
+            bg_threads.append(t)
+
+        for i in range(100):
+            threading.setprofile_all_threads(my_profile)
+            threading.setprofile_all_threads(None)
+
+        done.set()
+        for t in bg_threads:
+            t.join()
+
+
 @threading_helper.requires_working_threading()
 class MonitoringMisc(MonitoringTestMixin, TestCase):
     def register_callback(self):