regent: Optimize cross product operator used in shards
regent: Optimize cross product operator used in shards

sdalton1/legion,sdalton1/legion,StanfordLegion/legion,StanfordLegion/legion,sdalton1/legion,sdalton1/legion,StanfordLegion/legion,sdalton1/legion,StanfordLegion/legion,chuckatkins/legion,sdalton1/legion,StanfordLegion/legion,chuckatkins/legion,chuckatkins/legion,StanfordLegion/legion,StanfordLegion/legion,chuckatkins/legion,chuckatkins/legion,chuckatkins/legion,StanfordLegion/legion,chuckatkins/legion