Removing non-wakeup alarms on user-removed

Alarms in mPendingNonWakeupAlarms were left hanging when the user is
removed. These would be defunct at the time of delivery, so there is no
point in holding on to them.

Test: atest AlarmManagerServiceTest

Fixes: 130444055
Change-Id: Ib496b26a855304556ed032b957a1c731f2e2ca18