Fix wrong report previous country code when releaseing airplane mode

1. Clears CellInfo in LocaleTracker in radio off state, to that the
previous remaining country code (iso) is not notified when radio off.
2. Avoid multiple time starts for EVENT_OPERATOR_LOST, On posting
EVENT_OPERATOR_LOST with SendingMessageDelayed, it is been overriden
/restarted with a new delay/multiple handler events, which seems to
causing abnormal behaviour.

Bug: 270659322
Bug: 278671974
Test: atest LocaleTrackerTest
Test: Manually Tested.
Change-Id: Id6588632c73761ff5427f7237d922cbc3fd07faf