Make it possible to make Tails use a simulated Tor network.
... provided by Chutney (https://gitweb.torproject.org/chutney.git). This is enabled iff the local configuration contains something like: Chutney: src_dir: "/path/to/chutney-src-tree" otherwise we'll use the real Tor network as we done previously. The main motivation here is improved robustness -- since the "Tor network" we now use will exit from the host running the automated test suite, we won't have to deal with Tor network blocking. Performance should also be improved. Will-fix: #9521