closely related to crbug/818798, the deps2submodules "resource" of the sync_submodules recipe module has been forked/cloned as a reusable lib (in infra/libs/...) as part of crbug/834330.  We should eliminate the original, so that we don't have two nearly identical code bodies, and have sync_submodules use the new one (assuming we keep sync_submodules at all).