suzerain: #3006 advance_controller(...final_statistics...)

Adds a new option flag, defaulting to false, permitting
forcing dumping a new statistics file on shutdown.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@42607 0bd85f0b-c151-43b9-a1e9-27231104551f