Remove alarms of cancelled pending intents

When a pending intent is cancelled, the alarm is essentially defunct.
Keeping around this alarm takes unneeded memory and unreasonably counts
towards the per-uid cap of pending alarms.

Test: Unit test:
atest com.android.server.AlarmManagerServiceTest
Existing CTS:
atest CtsAlarmManagerTestCases

Bug: 132379078
Change-Id: I4c6d59d9ac79708d8daf40657e9773c715271f1e
2 files changed