minitest notebook reports the wrong number of redshift tasks

[sbailey]

Minor, but filing a ticket because I can't fix this right now:

The minitest notebook has a print message "Running 736 redshift tasks". It is actually only running 46 redshift tasks, but using 736 cores to do so. Fix that.

(alas, it is has been surprisingly difficult to get all the bookkeeping right for number of tasks vs. number of cores vs. number of nodes...)