Fixes the unhandled promise rejection

spec/javascripts/repo/components/repo_sidebar_spec.js

@@ -161,6 +161,8 @@ describe('RepoSidebar', () => {
         window.dispatchEvent(popEvent);
 
         expect(Helper.getContent.calls.mostRecent().args[0].url).toContain(file1.url);
+
+        window.history.pushState({}, null, '/');
       });
     });
   });

spec/javascripts/vue_mr_widget/services/mr_widget_service_spec.js

@@ -31,6 +31,7 @@ describe('MRWidgetService', () => {
   });
 
   it('should have methods defined', () => {
+    window.history.pushState({}, null, '/');
     const service = new MRWidgetService(mr);
 
     expect(service.merge()).toBeDefined();