MessageCache: Add STRAIGHT_JOIN to avoid planner oddness

MessageCache: Add STRAIGHT_JOIN to avoid planner oddness

For some unknown reason, when the `actor` table has few enough NS8 rows
compared to `page` MariaDB 10.1.37 decides it makes more sense to fetch
everything from `actor` then join `revision` then `page` rather than
fetching the rows from `page` in the first place.

We can work around it by telling it to not reorder the query, but then
we also have to reorder it ourselves to put `page` first instead of
`revision`.

Bug: T231196
Change-Id: I2b2fb209e648d1e407c5c2d32d3ac9e574e361d5