Fix ListView is not scrolled properly with arrows

According to ListView's layoutChildren logic, it detaches all children
and rebuilds its children based on visible area which might omit
invisible elements in the adapter.

In this case, arrowScroll methods only tries to find next scroll
candidates from its children so user is unable to scroll more with
D-pad.

This fixes the issue by look forward next child among the adapter as
well as children.

Bug: 7346868
Change-Id: I01ab19ad899b5bcb5ab420ddf08c9ffd136933d1

Conflicts:
	core/java/android/widget/ListView.java