Currently, the SyncSourceResolver finds a valid sync source and does three remote calls on that node. The first is to make sure that we aren't too stale to sync from the node, and the other two are related to rollback-via-refetch. After EMRC=false is removed from the code base, we should be able to remove those last two remote calls, so that the only check in SyncSourceResolver is the "too stale" check.