Add a bench to test SkTileImageFilter.

Tests in three modes: no tiling, 32x32 tiled rendering, and 64x64 tiled
rendering.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1559403003

Review URL: https://codereview.chromium.org/1559403003
1 file changed