Closing alarm activity without dismissing or snooze stops next alarm from being scheduled

[pudup]

If an alarm goes off and you press home, the alarm will continue going off in the background. If you clear the notification away it will be impossible to stop the alarm at that point barring one way. The one way to stop the alarm is to close the clock app from recents. Doing this prevents the next alarm from being scheduled and you'll have to disable and enable the alarm.

The notification for the alarm should prolly changed to an "Ongoing" notification.

Originally posted by @pudup in #490 (comment)