Decrement while removing from secondary lists

Many times alarms are moved to secondary lists like
mPendingWhileIdleAlarms. A cancel or a remove request will then remove
these alarms from here, in which case we need to decrement the alarm
counts appropriately.
Also, stubbing the handler in the test to fix flaky behaviour.

Test: atest CtsAlarmManagerTestCases
atest FrameworksMockingServicesTests:AlarmManagerServiceTest

Bug: 129995049
Bug: 130376760
Change-Id: I353f2b55cfd9566945b27b0807689a9d3e7c50fc