Provide an option to recompute the change tree

[amchiclet]

1. Infer type qualifiers on the project jolden-health.
2. Select then apply the change Change field next to @Nullable ListNode. Expand the change.
3. Select then apply the change Change field curNode to @Nullable ListNode.
4. Select then apply the change Change field head to @Nullable ListNode. Expand the change.
5. Under this change, the user can see the change Change field curNode to @Nullable ListNode which has actually already been fixed by one of the changes above. The reason the tree is not updated right away after every change is that it is an expensive operation. We should consider giving the user an option to recompute the changes tree to allow the user to see the updated tree when the user wants to.