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


DEBUG:Going to execute:
lazymatch Zify.zify_convert_to_euclidean_division_equations_flag
           with
           | true =>
               Zify.zify_internal_to_euclidean_division_equations
           | false => idtac
           end