Z instruction in Path statement is not handled correctly

[dinther]

Although earlier implementations were incorrect. The latest change made it impossible to generate open ended point lists.

pts=svgPoints("M0 0H100V100H0")[0];
echo("points are: ",pts);

ECHO: "points are: ", [[0, 0], [100, 0], [100, 100], [0, 100], [0, 0]]

Expected is

ECHO: "points are: ", [[0, 0], [100, 0], [100, 100], [0, 100]]

Although typically paths in the context of polygons are closed by the nature of a polygon, this is not always desired when a pathBuilder is used to generate a list of points.