Bug: 2-hop circuit with purpose 5 has no guard state

When I issue an "extendcircuit 0 A,B" command with my controller, and the circuit gets built, my Tor logs a line like:

Feb 09 20:36:44.400 [warn] circuit_build_no_more_hops(): Bug: 2-hop circuit 0x5558a75e2190 with purpose 5 has no guard state (on Tor 0.4.5.5-rc-dev f420eacf1858220f)

My extendprobe tester (tpo/network-health/team#16) makes many such circuits, and ends up with many such Bug lines.

See #24966 (closed) for a past version of this bug that got closed.

This issue isn't a big deal, except for the log spam, and maybe we still (hopefully we still?) have an invariant goal where Tor isn't supposed to issue any "Bug" lines during ordinary expected behavior.