Add ServiceWorker InstallPhaseEvent.waitUntil() layout test.

LayoutTests/http/tests/serviceworker/controller-on-load.html

Index: LayoutTests/http/tests/serviceworker/controller-on-load.html
diff --git a/LayoutTests/http/tests/serviceworker/controller-on-load.html b/LayoutTests/http/tests/serviceworker/controller-on-load.html
index 2e25776c448b9739c70553331eaa605a3f82326c..e76e554253d87392b4d98a0870632300bcaeba02 100644
--- a/LayoutTests/http/tests/serviceworker/controller-on-load.html
+++ b/LayoutTests/http/tests/serviceworker/controller-on-load.html
@@ -13,7 +13,7 @@ t.step(function() {
 
     function onRegister(worker) {
         worker.addEventListener('statechange', t.step_func(function(event) {
-            if (event.target.state == 'active')
+            if (event.target.state == 'activated')
                 onActive();
         }));
     }