Avoid OOBE when AbsListView layout is out of sync with adapter

Views are not synchronized with adapter state until a layout pass
occurs, which may cause an OOBE if a list item is removed and an
accessibility node is obtained before the next layout pass.

This CL caches the item's enabled state on the bound view's layout
params, which allows us to avoid relying on the adapter to populate
accessibility nodes. It also aborts actions if the target position
is no longer valid.

Updates the documentation on AdapterView to reflect that the result
of getPositionForView() may not be synchronized with the adapter.

Bug: 23943664
Change-Id: I90ca946bead1d87a179eab1c2f482a54bcce9c38