[Stress] Remove unused periodic_task

funtests/stress/stress/app.py

@@ -175,8 +175,3 @@ def marker(s, sep='-'):
             return _marker.delay(s, sep)
         except Exception as exc:
             print("Retrying marker.delay(). It failed to start: %s" % exc)
-
-
-@app.on_after_configure.connect
-def setup_periodic_tasks(sender, **kwargs):
-    sender.add_periodic_task(10, add.s(2, 2), expires=10)