Add ability to fuzz images using scaling and different modes

This also fixes the tryAllocPixels/SkColorTable mismatch which was causing the
"Image might be too large (32 x 32)" problems.

BUG=skia:4952
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1698963003

Review URL: https://codereview.chromium.org/1698963003
1 file changed