message: Report number of moves played at end of selfplay game
diff: @@ -289,6 +289,7 @@ class SelfPlayer {
  std::cout << player->result_string() << std::endl;
  std::cout << "Playing game: " << absl::ToDoubleSeconds(game_time)
  << std::endl;
  + std::cout << "Played moves: " << player->root()->position.n() << std::endl;
  const auto& history = player->history();
  if (history.empty()) {
  