remove cruft from SkTypes.h, including SkBool

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1548223002

TBR=

Review URL: https://codereview.chromium.org/1548223002
11 files changed