Also removes tests for the class.
Bug: T119253
Change-Id: I4c0d7187c2b847297dd0867faecba26185cfba37
Depends-On: Iccafbbdb06711463fee0f30a11326c7771df30e2
The new locateUsersWatchingTitle implementation could end up returning
thousands of users, currently on enwiki there are 25 titles with more
than 10k subscribed users and aprox 550 titles with more than 1k subscribed
users.
This switches the user collection to an iterator based implementation so that
we no longer need to have the entire users list at any one time.
Change-Id: I3d3fa9328f348bb48682d3658622952ce82d3925