[test] Deflake prefetching.stale-times (#85733)

Author: eps1lon

test/e2e/app-dir/app-prefetch/prefetching.stale-times.test.ts

@@ -129,6 +129,8 @@ describe('app dir - prefetching (custom staleTime)', () => {
 
   it('should not re-fetch cached data when navigating back to a route group', async () => {
     let act: ReturnType<typeof createRouterAct>
+    // Just installing so that the page doesn't automatically move past dynamic stale time
+    createTimeController()
     const browser = await next.browser('/prefetch-auto-route-groups', {
       beforePageLoad(page) {
         act = createRouterAct(page)