only in patch2:
unchanged:
--- a/core/modules/system/src/Tests/Theme/FunctionsTest.php
+++ b/core/modules/system/src/Tests/Theme/FunctionsTest.php
@@ -64,7 +64,6 @@ function testItemList() {
     // Verify that title set to a render array is output.
     $variables = array();
     $variables['title'] = array(
-      '#theme' => 'markup',
       '#markup' => '<span>Render array</span>',
     );
     $variables['empty'] = 'No items found.';