Fix a bug in threading that causes threads to fail to start. #41149

Author: BarneyStratford

Lib/threading.py

@@ -884,8 +884,7 @@ def run(self):
 
         """
         try:
-            if self._target:
-                self._target(*self._args, **self._kwargs)
+            self._target(*self._args, **self._kwargs)
         finally:
             # Avoid a refcycle if the thread is running a function with
             # an argument that has a member that points to the thread.