Counter::movedBy stored the mark as it stood, so 'never marked' and 'marked
before any work was done' were both zero — and a paced signal fired for ever at
the start of a session, which is exactly when nothing has happened worth saying.
The mark is held one past itself now, so the two stay different facts.

The routine's own test simulated a stretch of work by filing journal entries,
which is the measure the pacing change abandoned. It does the work instead.