Tests: Pre-declare the `$year_url` property before initialization in `Tests_Get_Archives::setUp()`.

Props pbearne.
Fixes #36611.


git-svn-id: https://develop.svn.wordpress.org/trunk@37271 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/functions/getArchives.php

@@ -10,6 +10,7 @@ $defaults = array(
 class Tests_Get_Archives extends WP_UnitTestCase {
 	protected static $post_ids;
 	protected $month_url;
+	protected $year_url;
 
 	function setUp() {
 		parent::setUp();