Further reduction of GPU workload in shapes benchmarks. Hopefully this squelches the random crashes on Mali 400.

BUG=skia:4937
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1703233002

Review URL: https://codereview.chromium.org/1703233002
1 file changed