Add an extra check to ensure that timer is actually expired.
Add an extra check to ensure that timer is actually expired.

Bug: 22181642

It's technically possible for the timer to receive a +1 between
times_up and the actual firing of the alarm.

Change-Id: Ie010958ae3553b940d7d82935eeaf4b236cf0c86

OrBin/SynClock-Android