Clones and resets this iterator. Note that the cloned iterator is
not restartable. This is because cloning is needed for variable
references, and the context node of the original variable
declaration must be preserved.
Default implementation of getLast(). Stores current position
and current node, resets the iterator, counts all nodes and
restores iterator to original state.
Initialize iterator using a node. If iterator is not
restartable, then do nothing. If node is equal to END then
subsequent calls to next() must return END.