Ran the three test case overnight; saw mostly no increase in mem usage. -- gc before every thread exit: up to 9M thread exits, no change in heap-size
-- gc before every third thread exit: 25M thread exits, no change. -- gc before every 17th thread exit: 44M thread exits, relatively small increase, from (heap-size . 1875902464) to (heap-size . 2068840448)
