py3: add 1 new passing test found by buildbot
This will make py3 buildbot green again.
Differential Revision: https://phab.mercurial-scm.org/D5861
--- a/contrib/python3-whitelist Mon Feb 04 21:23:44 2019 -0800
+++ b/contrib/python3-whitelist Tue Feb 05 21:17:46 2019 +0300
@@ -760,5 +760,6 @@
test-wireproto-serverreactor.py
test-wireproto.py
test-wireproto.t
+test-worker.t
test-wsgirequest.py
test-xdg.t