Recreate all AlarmInstances on restore

This approach guarantees that no AlarmInstance state from the
backup device influences behavior on the restore device.

All newly scheduled AlarmInstances will be for the future. There
cannot be, for example, notifications for AlarmInstances that
were missed on the backup device.

Bug: 22798579
Change-Id: Ia73bcc16c683cb0e3602f39028a347b30900fbd4