Update to Drupal 8.0.0-beta15. For more information, see: https://www.drupal.org/node/2563023

core/modules/action/action.views_execution.inc

@@ -11,14 +11,12 @@ use Drupal\Component\Utility\SafeMarkup;
  * Implements hook_views_form_substitutions().
  */
 function action_views_form_substitutions() {
-  // Views SafeMarkup::checkPlain()s the column label, so we need to match that.
-  $select_all_placeholder = SafeMarkup::checkPlain('<!--action-bulk-form-select-all-->');
   $select_all = array(
     '#type' => 'checkbox',
     '#default_value' => FALSE,
     '#attributes' => array('class' => array('action-table-select-all')),
   );
   return array(
-    $select_all_placeholder => drupal_render($select_all),
+    '<!--action-bulk-form-select-all-->' => drupal_render($select_all),
   );
 }