regent: Enable SPMD in stencil_fast.rg.
regent: Enable SPMD in stencil_fast.rg.

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