removed useless test

src/optimize_machine.ml

@@ -966,7 +966,7 @@ let add_ghost_assigns_reassigned rasg instrs =
           (fun i ->
             match VMap.find_opt i rasg with
             | Some ns ->
-              IntS.is_empty ns || IntS.exists (( = ) n) ns
+              IntS.exists (( = ) n) ns
             | _ ->
               false)
           il