Fix visit of list-like AST nodes.

Fix visit of list-like AST nodes.

The method finish() of a list-like node will convert the circular
list to a single-list. The right way to iterate is by looking
at the member `next' and by invokign finish().

Change-Id: I85a45b691a6c7089cd1a765871a11a7c60c3cdff
Reviewed-on: http://codereview.qt.nokia.com/3780
Reviewed-by: Roberto Raggi <roberto.raggi@nokia.com>
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>