The bug shows up when doing cairo_copy_path_flat for a path that has
a curve_to immediately after a close_path. When the curve is flattened
the flattener is using (0,0) as the initial point rather than the proper
close_to point.
This test also serves to ensure a similar bug doesn't crop up when
closing a path that begins with an implicit move_to, (as from cairo_arc).
In that bug the path state may have no last-move-point and the path
is closed to (0,0). This bug is not present currently, but did appear
during the development of a fix for the bug above.
