increase subdivision for very large cubics

Allow 512 subdivisions for hairline cubics instead of 64
to allow very large cubics to be properly approximated with
lines.

R=reed@google.com
BUG=339297
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1674813002

Review URL: https://codereview.chromium.org/1674813002
2 files changed