fuzz: list API fuzzing options if -t api and -n matches nothing.

Today we segfault if --name is empty.  This fixes that too.

This updates some terms: -t api lets us fuzz an API.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1617713003

Review URL: https://codereview.chromium.org/1617713003
1 file changed