test: in dijkstra, use the same K as in the lustre version

test/dijkstra-ring/p.ml

-(* Time-stamp: <modified the 16/01/2023 (at 22:13) by Erwan Jahier> *)
+(* Time-stamp: <modified the 08/04/2024 (at 17:01) by Erwan Jahier> *)
 
 open Algo
 
-let k = card()
+let k = card()+1
 open State
 let (init_state: int -> string -> 's) =
   fun _ _ ->