Scan 0.2.9.x relays to see if they're serving an out-of-date consensus?

In #20499 (moved) we see a potential bug where relays opt to stop getting directory information.

How pervasive is this bug in practice?

Doing a scan of these relays to see which consensus they give us could be quite enlightening.

Also, once we have a module in our scanners to do this test, it would probably be wise to automate running it every so often, as an early (ok, not so early really) warning system to catch regressions.

(In theory all 0.2.9 relays should be caching directory stuff now, right?)