Revert "Merge pull request #18340 from cpennington/fix-studio-xblock-rendering"

This reverts commit 9a70ca78a5, reversing
changes made to efd5b9abbd.

Hopefully fixes EDUCATOR-3053

cms/static/js/spec/utils/drag_and_drop_spec.js

@@ -309,7 +309,6 @@ define(['sinon', 'js/utils/drag_and_drop', 'common/js/components/views/feedback_
                 });
                 afterEach(function() {
                     this.clock.restore();
-                    jasmine.stealth.clearSpies();
                 });
                 it('should send an update on reorder from one parent to another', function() {
                     var requests, request, savingOptions;