Move LocationTimeZoneEvent to com.android

LocationTimeZoneEvent was originally supposed to fulfil the same role as
Location does in the LocationProvider. Since Location is public SDK, it
was in android.location. LocationTimeZoneEvent is not public SDK (or any
form of API), so it can be moved to com.android instead.
LocationTimeZoneEventUnbundled is in the API in its place.

Bug: 169304499
Test: treehugger only
Change-Id: I5d382362383000b16852928895a18ac4e4269a8f