Reset context after doing non-Skia GL rendering.

Fixes nanobench crash in GLInstancedArraysBench

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1969623003

Review-Url: https://codereview.chromium.org/1969623003
1 file changed