The internal lb subtests raced the previous subtest's sys.micro VM
deallocation: fixed 15s sleeps were not enough on capacity-tight
single nodes, so the LB entered terminal state failed (insufficient
capacity, then nats no-responders after the daemon unsubscribed the
full topic).
Replace the sleeps with createActiveLB: create LB + listener, wait for
active via the new non-fatal harness WaitForLBActiveErr, and on a
terminal failed state (wraps ErrLBTerminalFailed) tear down fully and
retry with backoff, up to 3 attempts.
joshsiv-mulga
96909d0e9a