[SVG] Fix polyline/polygon point parsing

This was evident in the 'shapes-polygon-01-t' SVG.

Change-Id: I4900b9e3626b924291c569a6611fb3b280e3219c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/282397
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Tyler Denniston <tdenniston@google.com>
1 file changed