fix test

Author: c-cube

tests/core/t_list.ml

@@ -124,6 +124,7 @@ eq
    fold_flat_map (fun acc x -> acc + x, [ pf "%d" x; pf "a%d" x ]) 0 [ 1; 2; 3 ])
 ;;
 
+[@@@ifge 4.12]
 t @@ fun () ->
 let r = Atomic.make 0 in
 let f x =
@@ -139,6 +140,8 @@ assert_equal
 true
 ;;
 
+[@@@endif]
+
 q
   Q.(list int)
   (fun l ->