Linfeng Zhang authored Dec 11, 2017 and James Zern committed Dec 14, 2017

Move get_nz_map_ctx() out of get_coeff_cost(), so that the coeff_ctx
won't be recalculated in get_dist_cost_stats().

Change-Id: I511d66e3e1a768c77314b290dc6bb90a123ca541