some fuzz hacking

some fuzz hacking

Try to start faster:
 - remove flags dependency
 - print nothing
 - strip unused symbols from the binary on Mac (smaller binary)
 - only create one fuzz object
 - only run one DEF_FUZZ
I am not sure if any of these things mattered, but I thought you may like to look.

Good stuff:
 - make nextU() / nextF() work
 - drop nextURange() / nextFRange() for now
 - add nextB() for a single byte

As you may have guessed, I have figured out how to use afl-fuzz on my laptop.

Syntax to run becomes:
  $ afl-fuzz ... out/Release/fuzz <DEF_FUZZ name> @@

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1581203003

Review URL: https://codereview.chromium.org/1581203003