Make accessibility anchor id a long

The anchors are, in practice, always Views, but they may end up
being virtual views in the future, so we should have this done
right.

Also cleaning up picture in picture mode. I don't know why I made
it a separate boolean when I already had the boolean properties.

Bug: 70730136
Test: A11y unit tests and CTS
Change-Id: I916ec066dff12fab8b586371452b728af6be1271