Revert "legion: remove now spurious assertions"
Revert "legion: remove now spurious assertions"

This reverts commit cb46cafbeb47fbecb58e5a4d0ce848fc8f14b9fb.

StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion