Fix test failure so it's no longer dependent on example.com.

Lib/test/test_urllibnet.py

@@ -89,7 +89,7 @@ class urlopenNetworkTests(unittest.TestCase):
 
     def test_getcode(self):
         # test getcode() with the fancy opener to get 404 error codes
-        URL = "http://www.example.com/XXXinvalidXXX"
+        URL = "http://www.pythontest.net/XXXinvalidXXX"
         with support.transient_internet(URL):
             with self.assertWarns(DeprecationWarning):
                 open_url = urllib.request.FancyURLopener().open(URL)