Avoid restarting Tor when time changes
According to the comment in our code, Tor is unreliable with picking a circuit after time change so we restart it. Is it still the case, or was it an old bug?
Restarting tor has several bad consequences: see #18446 (closed) for one example. It also had impacts on D:Sponsor08 work, leading us to bring the "always saveconf" approach (see 3be18d9f and #18303 (closed)). So avoiding this restart could be valuable.
So this issue is about:
- understanding if Tor is really unreliable with picking a circuit after time change
- see if a SIGHUP can be enough when this happens