[ticket/17176] Fix some PHP 8.x deprecations and clean up test code

PHPBB3-17176

tests/migrations/migrations_check_config_added_test.php

@@ -13,6 +13,36 @@
 
 class migrations_check_config_added_test extends phpbb_test_case
 {
+	/** @var \phpbb\config\config */
+	protected $config;
+
+	/** @var \Symfony\Component\DependencyInjection\ContainerInterface */
+	protected $container;
+
+	/** @var \phpbb\db\driver\driver_interface */
+	protected $db;
+
+	/** @var \Doctrine\DBAL\Connection */
+	protected $db_doctrine;
+
+	/** @var \phpbb\db\tools\tools_interface */
+	protected $db_tools;
+
+	/** @var \phpbb\extension\manager */
+	protected $extension_manager;
+
+	/** @var \phpbb\db\migrator */
+	protected $migrator;
+
+	/** @var string */
+	protected $table_prefix;
+
+	/** @var string */
+	protected $phpbb_root_path;
+
+	/** @var string */
+	protected $php_ext;
+
 	protected function setUp(): void
 	{
 		global $phpbb_root_path;