Issue #2679547 by Wim Leers: Fix random fail in ConfigImportAllTest caused by...

Issue #2679547 by Wim Leers: Fix random fail in ConfigImportAllTest caused by ModuleInstaller not rebuilding routes immediately, which happens to be surfaced by BigPipe

core/modules/system/system.routing.yml

@@ -445,6 +445,8 @@ system.batch_page.html:
     _format: 'html'
   options:
     _admin_route: TRUE
+    # @todo Remove the '_no_big_pipe' route option when https://www.drupal.org/node/2589967 lands.
+    _no_big_pipe: TRUE
 
 system.batch_page.json:
   path: '/batch'