Summary:
Following up on the previous diff to remove the only usage of `listKey` for persistent association, we can remove the need for a manual `listKey`, and instead rely on per-instance association via refs.
A followup change will remove the existing usages.
Changelog:
[General][Removed] - Remove VirtualizedList `listKey` prop
Reviewed By: p-sun
Differential Revision: D39466677
fbshipit-source-id: 6b49f45c987fff9836918ba833fbb16f24414ff8
