We're currently use jafar for QA and jafar is a better mechanism,
even though it is not portable outside of Linux.
This self censorship mechanism was less cool and added a bunch
of (also cognitive) complexity to netx.
If we ever want to go down a self censorship like road, we probably
want to do as little work as possible in the problem and as much
work as possible inside a helper like jafar.
Part of https://github.com/ooni/probe/issues/1591.
