This change should make it impossible for the monotonic time to roll
over from one EWMA tick to the next during this test, and make it so
that this test never invokes scale_active_circuits() (which it
doesn't test).
(Earlier changes during the 0.3.4 series should make this call even
rarer than it was before, since we fixed#25927 and removed
cached_gettimeofday. Because this test didn't update
cached_gettimeofday, the chance of rolling over a 10-second interval
was much higher.)
Closes ticket 25994; bugfix on 0.3.3.1-alpha when this test was
introduced.
