This is the slowest test in the sharness test suite, because it has
very long sleeps. It usually takes 2+ minutes to run.
This new impl runs all peering tests in about 20 seconds, since it
polls for conditions instead of sleeping, and runs the tests in
parallel.
This also has an additional test case for a peer that was never online
and then connects.
This is intended as a replacement for sharness. These are vanilla Go
tests which can be run in your IDE for quick iteration on end-to-end
CLI tests.
This also removes IPTB by duplicating its functionality in the test
harness. This isn't a big deal...IPTB's complexity is mostly around
the fact that its state needs to be saved to disk in between `iptb`
command invocations, and that it uses Go plugins to inject
functionality, neither of which are relevant here.
If we merge this, we'll have to live with bifurcated tests for a while
until they are all migrated. I'd recommend we self-enforce a rule
that, if we need to touch a sharness test, we migrate it and one more
test over to Go tests first. Then eventually we will have migrated
everything.
