Sleep 1 sec in mininode's wait_for_disconnect (dashpay#3538)

* Sleep 1 sec in mininode's wait_for_disconnect

* Add a comment about a future backport that might potentially fix related issues

Author: UdjinM6

test/functional/test_framework/mininode.py

@@ -373,6 +373,8 @@ def on_version(self, message):
     def wait_for_disconnect(self, timeout=60):
         test_function = lambda: self.state != "connected"
         wait_until(test_function, timeout=timeout, lock=mininode_lock)
+        # This is a hack. The related issues should be fixed by bitcoin 14119 and 14457.
+        time.sleep(1)
 
     # Message receiving helper methods