Mark ‘core <-> relay <-> core’ test as failing.
I’ve tried debugging it, but I can’t see how it’s ever supposed to work.
The termination condition deadlocks, and when that’s adjusted, the
resulting chains shows the two core nodes end up with different chains.
But it’s unclear what this is testing because the nodes are not doing
normal chain selection (they call fixupBlock).
In any case, we almost certainly are going to delete the Node and
corresponding tests from the network package, since this is handled in
the consensus package now (using real chain selection).
