TimeSparseArray - used to store UsageEvents - can keep at most one event
per millisecond, which can result in an event being replaced by another
event that occurred close enough that the system records it at the same
millisecond.
Test: atest android.app.usage.TimeSparseArrayTest
Fixes: 73832306
Change-Id: I860a101ab098f65d5c5832758832f43572865690
2811d92483