Fix hit_rate_curve to ignore huge stack distances.
Fix hit_rate_curve to ignore huge stack distances.

They get tracked as 'too_big' and the final curve is adjusted
correctly, though we can't draw the whole curve that covers
those accesses.

utah-scs/lsm-sim,utah-scs/lsm-sim,utah-scs/lsm-sim,utah-scs/lsm-sim