Fix issue with cookie support testing

I noticed this while checking the Jasmine version, now that I'm running in a local browser. If testing in an environment where no cookies are set *yet*, the tests assume cookies aren't supported, which is not correct. This fixes the issue.

test/test-helpers.js

@@ -48,7 +48,7 @@ define(function () {
     };
 
     self.isCookieStorageAvailable = function isCookieStorageAvailable() {
-        if (window && window.document && window.document.cookie) {
+        if (window && window.document && window.document.cookie != null) {
             // We need to check not just that the cookie objects are available, but that they work, because
             // if we run from file:// URLs they appear present but are non-functional
             window.document.cookie = "test=hi;";