Goal:
    z : Z  z0 : Z  z1 : Z  H : (z <= z1)%Z  H0 : (z0 <= z1)%Z
  ============================
   (Z.max z z0 <= z1)%Z


DEBUG:Going to execute:
intros; Zify.zify_pre_hook; zify_elim_let; zify_op;
            Zify.zify_iter_specs; Zify.zify_to_euclidean_division_equations;
            Zify.zify_post_hook; zify_saturate