backport threading test change from python 3.11

Author: timfel

graalpython/lib-python/3/test/test_threading.py

@@ -856,8 +856,9 @@ def test_4_daemon_threads(self):
 
             def random_io():
                 '''Loop for a while sleeping random tiny amounts and doing some I/O.'''
+                import test.test_threading as mod
                 while True:
-                    with open(os.__file__, 'rb') as in_f:
+                    with open(mod.__file__, 'rb') as in_f:
                         stuff = in_f.read(200)
                         with open(os.devnull, 'wb') as null_f:
                             null_f.write(stuff)