skip stroke outset of all teeny lines

Allow a small amount of slop when seeing
if the previous moveTo and subsequent lineTo
are the same.

R=robertphillips@google.com
BUG=593049
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1805913002

Review URL: https://codereview.chromium.org/1805913002