Fall back from analytic to sampling earlier

This magically fixes some strange js unit tests in Chrome. Those tests
only fail in virtual/gpu which somehow interacts with my cpu rasterizer?

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2439973004

Review-Url: https://chromiumcodereview.appspot.com/2439973004
1 file changed