[canvaskit] Add test for skottie to catch framebuffer issues

Would have helped notice
https://skia-review.googlesource.com/c/skia/+/241757
when Gold results changed.

Change-Id: I0c7b75a7c6cd5d9952eb98056c98b1118471c330
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/241763
Reviewed-by: Nathaniel Nifong <nifong@google.com>
4 files changed