With the final goal to remove the real mw stubs, move the processLinks
tests away from test cases, and split getTitle to be tested standalone.
Supporting changes:
* Move getTitle out to it's own module
* Will be tested separately in a followup commit
* Remove global declaration of mw.popups.processLinks (not needed any more)
Bug: T160406
Change-Id: Ieebd1257a2476081c67a318d3f05dffa1d3b9bdd
