QA: Improve user page title selector for tests

Pages on test2wiki have a ShortUrl as part of the title, so "I am on my
user page" in post_links.feature fails.  This tightens up the selector
for page title.  Test passes on test2wiki and still passes on ee-flow.

Bug: 67788
Change-Id: I4fe54d29689650b4dafd63dc77eae374029d27ec
Merge "QA: Improve user page title selector for tests"