TestingTorNetwork doesn't lower the dir fetch retry schedules

https://trac.torproject.org/projects/tor/ticket/6341#comment:34 shows a lot of socks timeouts from Tor clients in a Testing Tor Network. Apparently these clients didn't get enough directory info to establish circuits, so they just fail all their application requests. The issue is apparently exacerbated by #3196 (moved) where we demanded more descriptors be present before we consider ourselves bootstrapped.

Perhaps the real problem here is that we keep the normal dir fetch retry schedules even when TestingTorNetwork is set? It looks like TestingTorNetwork makes a new consensus every 5 minutes, but client_dl_schedule is "0, 0, 60, 605, 6010, INT_MAX".

Should we lower the retry schedules?

Has it been the case this whole time that clients in testing networks typically don't have all the descriptors they'd want?