only in patch2:
unchanged:
--- a/core/modules/field/tests/src/Kernel/Migrate/d6/MigrateFieldInstanceTest.php
+++ b/core/modules/field/tests/src/Kernel/Migrate/d6/MigrateFieldInstanceTest.php
@@ -81,6 +81,7 @@ public function testFieldInstanceMigration() {
       'uri_scheme' => 'public',
       'handler' => 'default:file',
       'handler_settings' => array(),
+      'serialize_embedded_entities' => FALSE,
     );
     $field_settings = $field->getSettings();
     ksort($expected);