Add new fuzz binary.

This is designed to have short startup time, for maximum fuzzing throughput.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1589563002

Review URL: https://codereview.chromium.org/1589563002
5 files changed