Minimum 1 frame timeline in java Choreographer

Sometimes the data from native gives an empty VsyncEventData (perhaps
erroneously), causing out-of-bound crashes in java Choreographer side.
Instead, the public FrameData should maintain at least 1 frame timeline
which will have the default data when accessed.

Bug: 290965823
Test: atest ChoreographerTest

Change-Id: I8b704433aca55bc9697fd843257ac62995e75a1f