node tests: Auto-include zblueslip for node tests.

We already use blueslip stubs in ~45 tests, so we
may as well just auto-include it.

frontend_tests/node_tests/list_render.js

@@ -9,8 +9,6 @@ set_global('Element', function () {
     return { };
 });
 
-set_global('blueslip', global.make_zblueslip());
-
 // We only need very simple jQuery wrappers for when the
 // "real" code wraps html or sets up click handlers.
 // We'll simulate most other objects ourselves.