Using a list to store usage events

Moving UsageEvent.Event objects to an array list sorted on the event
timestamps as there can be multiple events with the same timestamps.

Test: atest android.app.usage.EventListTest
Existing tests:
atest android.app.usage.cts.UsageStatsTest

Bug: 74406113
Change-Id: Idc7f2a8db6e5a9499b3b0b74efbf014b17fa495f
7 files changed