For S55 we are trying to get self-tests and remote-tests working with IPv6. To make sure we've succeed, we need to try them with Chutney. But to try them with chutney, we need them to be enabled. With legacy/trac#33583 we removed AssumeReachable from the chutney configurations. But that didn't actually have any effect, since `AssumeReachable 1` is implicit in `TestingTorNetwork 1`.