Add GrContext::releaseAndAbandonContext()

Like abandonContext() this disconnects the GrContext from the underlying 3D API. However, unlike abandonContext it first frees all allocated GPU resources.

BUG=skia:5142
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1852733002

Review URL: https://codereview.chromium.org/1852733002
15 files changed