Use SkOpts routines in SkSwizzler

This is a bit tricky because we don't intend to support sampling
in SkOpts.  The swizzler will fallback to a default routine in
the event that sampling is requested.

BUG=skia:4767
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1563393002

Review URL: https://codereview.chromium.org/1563393002
3 files changed