Improve kernel test dates to prevent "random" fails

seanB → closed merge request !14

The code below currently seems to break the tests. The queue table might not exist the first time something is added to the queue, so we can't query it. We should check if the queue table exists.

  public function nodeExistsInQueue(int $nid): int {
    $query = $this->connection->select(DatabaseQueue::TABLE_NAME, 'q');
    $query->condition('name', 'node_revision_delete');
    $query->condition('data', serialize($nid));
    $query->condition('expire', 0);
    $query->fields('q', ['item_id']);

    $result = $query->execute()->fetchCol();

    return !empty($result) ? $result[0] : 0;
  }

Pushed a commit to add a check if the queue table exists.