Update argument checks in link building

RevisionFormatter::buildActionLinks was recently updated such
that $revId is no longer an optional parameter.  This patch
removes all the $revId checks and updates any missing $postId
checks.

Change-Id: I0fa46f09e4ff6f9e8cd0879a16e75a3d1f02ab18
Repair checkuser unit test

A recent patch updated CheckUser to work more like the other
query/formatter combos.  Unfortunatly the test cases didn't
get updated along with it.

Change-Id: I14e0cccdc2bd278262aeb3b57dea2725e416b042
Merge "Update argument checks in link building"
Merge "Repair checkuser unit test"