test_classes: Use mock.patch in tornado_redirected_to_list.
test_classes: Use mock.patch in tornado_redirected_to_list.

Signed-off-by: Anders Kaseorg <dfdb7392591db597bc41cf266a9c3bc12a2706e5@zulip.com>

kou/zulip,eeshangarg/zulip,rht/zulip,kou/zulip,kou/zulip,andersk/zulip,zulip/zulip,hackerkid/zulip,zulip/zulip,eeshangarg/zulip,hackerkid/zulip,rht/zulip,kou/zulip,kou/zulip,hackerkid/zulip,eeshangarg/zulip,eeshangarg/zulip,zulip/zulip,zulip/zulip,hackerkid/zulip,andersk/zulip,zulip/zulip,rht/zulip,eeshangarg/zulip,andersk/zulip,hackerkid/zulip,zulip/zulip,eeshangarg/zulip,hackerkid/zulip,andersk/zulip,rht/zulip,andersk/zulip,eeshangarg/zulip,hackerkid/zulip,rht/zulip,andersk/zulip,andersk/zulip,rht/zulip,rht/zulip,kou/zulip,zulip/zulip,kou/zulip