Add --benchType and --sourceType to nanobench.

To run only codec benches:
   $ out/Release/nanobench --images <> --benchType skcodec

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1666743002

Review URL: https://codereview.chromium.org/1666743002
1 file changed