This forces all the loop bodies to be executed at least once, which is
harmless since it just means one more tox event loop iteration. This
reduces the jitter we see in coverage measurements, which is partially
caused by loops sometimes being entered and sometimes not (because their
condition happens to randomly already be true).
Also, add an auto-test for bootstrap and for LAN discovery.
Bootstrap is never tested otherwise, and LAN discovery is a prerequisite
for everything else. Having these two tests lets us rule out or identify
LAN discovery as a possible cause for test failures.
