node_tests: Add missing stream_id field to tests in stream_data.

These were resulting in inadvertant calls to blueslip.fatal but
the code continued beyond that point, since in our testing environment
we do not stop executing when fatal is called.

This commit also adds checks to ensure that the subs were created.

frontend_tests/node_tests/stream_data.js

@@ -625,14 +625,17 @@ run_test('initialize_from_page_params', () => {
     function initialize() {
         page_params.subscriptions = [{
             name: 'subscriptions',
+            stream_id: '2001',
         }];
 
         page_params.unsubscribed = [{
             name: 'unsubscribed',
+            stream_id: '2002',
         }];
 
         page_params.never_subscribed = [{
             name: 'never_subscribed',
+            stream_id: '2003',
         }];
     }
 
@@ -640,6 +643,10 @@ run_test('initialize_from_page_params', () => {
     page_params.realm_notifications_stream_id = -1;
     stream_data.initialize_from_page_params();
 
+    const stream_names = stream_data.get_streams_for_admin().map(elem => elem.name);
+    assert(stream_names.indexOf('subscriptions') !== -1);
+    assert(stream_names.indexOf('unsubscribed') !== -1);
+    assert(stream_names.indexOf('never_subscribed') !== -1);
     assert(!page_params.subscriptions);
     assert(!page_params.unsubscribed);
     assert(!page_params.never_subscribed);