Remove "ExtraAssertations"

Author: sethmlarson

Lib/test/test_urllib.py

@@ -13,7 +13,6 @@
 from test.support import socket_helper
 from test.support import warnings_helper
 from test.support import control_characters_c0
-from test.support.testcase import ExtraAssertions
 import os
 try:
     import ssl