[canvaskit] Change contexts when making surfaces from GrContext

Suggested by jason-simmons
https://github.com/flutter/flutter/issues/95259#issuecomment-1026390189

Change-Id: Id523648dc4d8db261577f2cf4b46d52cc3335451
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/502310
Reviewed-by: Nathaniel Nifong <nifong@google.com>
2 files changed