MAGETWO-75530: Deadlock when 'Asynchronous indexing' is enabled (insert from select on sales_order_grid).

Author: le0n4eg

app/code/Magento/Sales/Test/Unit/Model/ResourceModel/GridTest.php

@@ -3,6 +3,8 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+declare(strict_types=1);
+
 namespace Magento\Sales\Test\Unit\Model\ResourceModel;
 
 use Magento\Framework\TestFramework\Unit\Helper\ObjectManager;