Skip degenerate contours in glyphs.

Stroking in Skia follows the SVG rules of adding end caps to degenerate
contours. Skip all degenerate contours and degenerate curves on contours
to avoid this.

Bug: skia:9820
Change-Id: I320beeeb3728f39c764729454dcb128a05524d35
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/268166
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Herb Derby <herb@google.com>
9 files changed