Tests: add back `persistence` test

In the past we commented out this test because it failed intermittently.
This was simply because the `otherUrl` variable didn't exist and an error
was thrown. Changing `otherUrl` with `about:blank` seemed to fix the issue.

Ref http://en.wikipedia.org/wiki/About_URI_scheme

browser-tests/test.js

@@ -285,7 +285,7 @@ module.exports.todoMVCTest = function (frameworkName, baseUrl, speedMode, laxMod
 			});
 		});
 
-		/*test.describe('Persistence', function () {
+		test.describe('Persistence', function () {
 			test.it('should persist its data', function () {
 				// set up state
 				page.enterItem(TODO_ITEM_ONE);
@@ -302,13 +302,13 @@ module.exports.todoMVCTest = function (frameworkName, baseUrl, speedMode, laxMod
 				stateTest();
 
 				// navigate away and back again
-				browser.get(otherUrl);
+				browser.get('about:blank');
 				browser.get(baseUrl);
 
 				// repeat the state test
 				stateTest();
 			});
-		});*/
+		});
 
 		test.describe('Routing', function () {
 			test.it('should allow me to display active items', function () {