[TIMOB-12218] Adding test case for `significanttimechange` event

__To be tested along with [TIMOB PR](https://github.com/appcelerator/titanium_mobile/pull/3867)__

GO TO PLATFORM > APPLICATION EVENTS
Background the app.
Change the time zone.(Settings > General > Date & Time > timezone)
Resume the app. You should see the Label change and an alert being fired.