pythongh-113205: test_multiprocessing.test_terminate: Give tasks a chance to start (pythonGH-114249)

(cherry picked from commit ce75b4c)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Author: serhiy-storchaka

Lib/test/_test_multiprocessing.py

@@ -2704,6 +2704,7 @@ def test_terminate(self):
         p = self.Pool(3)
         args = [sleep_time for i in range(10_000)]
         result = p.map_async(time.sleep, args, chunksize=1)
+        time.sleep(0.2)  # give some tasks a chance to start
         p.terminate()
         p.join()