remove stray comment in #1157

Author: tanyongkiam

translator/ml_translatorLib.sml

@@ -1755,7 +1755,6 @@ val th = inv_defs |> map #2 |> hd
     val (x1,x2) = cases_th |> CONJUNCTS |> hd |> concl |> repeat (snd o dest_forall)
                            |> dest_eq
     val case_const = x1 |> repeat rator
-    (* val _ = persistent_skip_case_const case_const *)
     val ty1 = case_const |> type_of |> domain
     val ty2 = x2 |> type_of
     val cases_th = INST_TYPE [ty2 |-> mk_vartype "'return_type"] cases_th