Ensure that the ratio of workers to queues is 2:1 and that there are at
least 2 queues regardless.  Fix a few race conditions (h/t Sue from
WiredTiger for some nice work) and cherry pick (for now) a commit that
fixes a bug I triggered and Keith fixed (in < 10min from report) related
to WiredTiger stats.  Ensure that my guesstimate for session_max is no
larger than WiredTiger can manage.  Continue to fiddle with the build
script.