reverted:
--- b/core/modules/system/src/Tests/Update/UpdatePathTestBase.php
+++ a/core/modules/system/src/Tests/Update/UpdatePathTestBase.php
@@ -299,7 +299,7 @@
       $this->assertFalse($needs_updates, 'After all updates ran, entity schema is up to date.');
       if ($needs_updates) {
         foreach (\Drupal::entityDefinitionUpdateManager()
+          ->getChangeSummary() as $entity_type_id => $summary) {
-          ->getChangeSummary() as $summary) {
           foreach ($summary as $message) {
             $this->fail($message);
           }
reverted:
--- b/core/modules/system/tests/modules/pager_test/pager_test.module
+++ a/core/modules/system/tests/modules/pager_test/pager_test.module
@@ -18,7 +18,7 @@
     return;
   }
 
+  foreach ($variables['items']['pages'] as $index => &$pager_item) {
-  foreach ($variables['items']['pages'] as &$pager_item) {
     $pager_item['attributes']['pager-test'] = 'yes';
   }
   unset($pager_item);