After MediaWiki change I308617427309815062d54c14f3438cab31b08a73
there's no longer a "default" user/page/revision in the database, so
the user/page/revision IDs in the tests should start at 1 and not 2.
Bug: T345984
Change-Id: I3271e4fdd52cf6e2074d8c9d3d5571a69b150476
Just to confirm that this works correctly, because I broke it a few
times in different ways while working on T321121.
In this scenario, discussiontools_item_revisions contains rows for
the oldest and newest revisions of pages containing each comment
distinguishable by name, as well as extra rows for the newest
revisions of comments indistinguishable by name, so that they can
be looked up by ID.
Change-Id: Ic8450a6b082ed343dd633d3a43c50696b5d6d2bb