Build/Test Tools: Fix and standardise calls to the tearDown() method in the test suite.

The parent method should be called after any test-specific teardown.

See #52625


git-svn-id: https://develop.svn.wordpress.org/trunk@50450 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/customize/custom-css-setting.php

@@ -55,8 +55,8 @@ class Test_WP_Customize_Custom_CSS_Setting extends WP_UnitTestCase {
 	 * Tear down the test case.
 	 */
 	function tearDown() {
-		parent::tearDown();
 		$this->setting = null;
+		parent::tearDown();
 	}
 
 	/**