Remove Dead Code from 8.x brance

I think there are bunch of code need to be removed from 8.x branch for clarity reasons.

Reading through code would never stepped into is very time consuming and misleading.

example:

/**
 *  Clones a node - prepopulate a node editing form
 */
function node_clone_node_prepopulate($original_node) {
  if (isset($original_node->nid)) {

    if (node_clone_is_permitted($original_node->type)) {
      $node = _node_clone_node_prepare($original_node, TRUE);
      // @FIXME
// drupal_set_title() has been removed. There are now a few ways to set the title
// dynamically, depending on the situation.
//
//
// @see https://www.drupal.org/node/2067859
// drupal_set_title($node->title);

      // Let other modules do special fixing up.
      $context = array('method' => 'prepopulate', 'original_node' => $original_node);
      \Drupal::logger('probe')->notice("I bet this is never called");
      \Drupal::moduleHandler()->alter('node_clone_node', $node, $context);
      // Make sure the file defining the node form is loaded.
      $form_state = array();
      $form_state['build_info']['args'] = array($node);
      $form_state->loadInclude('node', 'inc', 'node.pages');
      return \Drupal::formBuilder()->buildForm($node->type .'_node_form', $form_state);
    }
  }
}