Add _jit_warned check to prevent parse-loop infinite recompilation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hosts/ocaml/bin/sx_server.ml

@@ -729,6 +729,7 @@ let register_jit_hook env =
        | None ->
          let fn_name = match l.l_name with Some n -> n | None -> "?" in
          if !_jit_compiling then None
+         else if Hashtbl.mem _jit_warned fn_name then None
          else begin
            _jit_compiling := true;
            let t0 = Unix.gettimeofday () in