Let gr-router use a local instance of page.js instead of a global one

This will be beneficial for testing apart from global variables being
a no-go anyway.

Release-Notes: skip
Change-Id: Idf9b07b79049deb79233043bc5d458fc15aeaa7c
diff --git a/polygerrit-ui/app/elements/core/gr-router/gr-router_test.ts b/polygerrit-ui/app/elements/core/gr-router/gr-router_test.ts
index 112c776..98272b4 100644
--- a/polygerrit-ui/app/elements/core/gr-router/gr-router_test.ts
+++ b/polygerrit-ui/app/elements/core/gr-router/gr-router_test.ts
@@ -5,7 +5,7 @@
  */
 import '../../../test/common-test-setup';
 import './gr-router';
-import {page, PageContext} from '../../../utils/page-wrapper-utils';
+import {Page, PageContext} from '../../../utils/page-wrapper-utils';
 import {
   stubBaseUrl,
   stubRestApi,
@@ -41,9 +41,11 @@
 
 suite('gr-router tests', () => {
   let router: GrRouter;
+  let page: Page;
 
   setup(() => {
     router = testResolver(routerToken);
+    page = router.page;
   });
 
   test('getHashFromCanonicalPath', () => {