Improve some queries ordering by rev_timestamp with actor migration READ_NEW
The revision_actor_temp table has denormalized copies of rev_page and
rev_timestamp to support the actor indexes equivalent to
`actor_timestamp` and `page_actor_timestamp`. But to get these to be
used, we need to have the WHERE and ORDER BY use the denormalized fields
instead of the main revision-table fields.
We can take generally advantage of the fact that "ORDER BY field" uses
aliased field names before the names in the actual table, but WHERE
conditions do need to explicitly vary.
Bug: T204669
Change-Id: I992aa50f02c35d76e91a5a28e05c870f8a32f858