Tests: Consistently use the expectException() method instead of the older @expectedException annotation.

See https://thephp.cc/news/2016/02/questioning-phpunit-best-practices

The method is available since PHPUnit 5.2, and WordPress currently supports PHPUnit 5.4 as the minimum version.

Follow-up to [48993].

See #51344.

git-svn-id: https://develop.svn.wordpress.org/trunk@48996 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/db.php

@@ -524,11 +524,10 @@ class Tests_DB extends WP_UnitTestCase {
 		$this->assertEmpty( $wpdb->check_database_version() );
 	}
 
-	/**
-	 * @expectedException WPDieException
-	 */
 	function test_bail() {
 		global $wpdb;
+
+		$this->expectException( 'WPDieException' );
 		$wpdb->bail( 'Database is dead.' );
 	}