[canvaskit] Fix drawPoints to be flattened point array

Bug: skia:11012
Change-Id: I0866f791f6fba82d073b5b5acd37aa8509b6fdef
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/339836
Reviewed-by: Yegor Jbanov <yjbanov@google.com>
Reviewed-by: Nathaniel Nifong <nifong@google.com>
3 files changed