Add blurcircles2 GM

In GM mode this draws an array of circles with different radii and different blur radii. Below each circle an almost-circle path is drawn with the same blur filter for comparison.

In Sample mode this draws a single circle and almost-circle with animating radius and blur radius.

BUG=skia:5224
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1974353003

Review-Url: https://codereview.chromium.org/1974353003
2 files changed