Zero-width strokes imply hairline in Skia, but in other models (e.g.
Lottie) they are simply ignored. The latter approach avoids
discontinuities when width -> 0, so let's make it the default for sksg.
TBR=
Change-Id: I957a873c0e6468e21372115ed18cc7316fd2e7d1
Reviewed-on: https://skia-review.googlesource.com/97661
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
739641580f