drupal_module__reinstall/src/EventSubscriber/TermPreDump.php

<?php

namespace Drupal\reinstall\EventSubscriber;

use Drupal\reinstall\DumperEvent;
use Drupal\reinstall\DumperEvents;
use Drupal\taxonomy\TermInterface;
use Drupal\taxonomy\TermStorageInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

class TermPreDump implements EventSubscriberInterface {

  public static function getSubscribedEvents() {
    return [
      DumperEvents::PRE_DUMP => 'onDumpPre',
    ];
  }

  protected static function setParents(TermInterface $term, $tid, TermStorageInterface $storage) {
    $parents = $storage->loadParents($term->id());
    if (!empty($parents)) {
      $term->set('parent', array_keys($parents));
    }
  }

  public static function onDumpPre(DumperEvent $event) {
    $storage = $event->storage;
    if ($storage->getEntityTypeId() !== 'taxonomy_term') {
      return;
    }

    array_walk($event->entities, [__CLASS__, 'setParents'], $storage);
  }
}