Add wait and amend assertion in test_clock_all_items_present_new_alarm


For the assertion on line 29, the text in the input is being set by the loading js and I have verified this viewing the html before and after the load event.
https://github.com/mozilla-b2g/gaia/blob/master/apps/clock/js/alarm.js#L913

I've omitted the picker assertion, it made redundant by the wait for it to be displayed.