message: add whole-board pass-alive check
diff: @@ -538,6 +538,14 @@ bool SelfplayGame::MaybePlayMove() {
  game_->MarkLastMoveAsTrainable();
  }
  + // If the whole board is pass-alive, play pass moves to end the game.
  + if (tree_->root()->position.n() >= kMinPassAliveMoves &&
  + tree_->root()->position.CalculateWholeBoardPassAlive()) {
  + while (!tree_->is_game_over()) {
  + tree_->PlayMove(Coord::kPass);
  + }
  + }
  +
  // TODO(tommadams): move game over logic out of MctsTree and into Game.
  if (tree_->at_move_limit()) {
  game_->SetGameOverBecauseMoveLimitReached(
  