Sheriff: Mark fast/canvas/OffscreenCanvas-copyImage.html as flaky on Linux

Bug: 865477, 923269
Change-Id: I437488d264cf29dfac03843203a362039e267d07
Tbr: nhiroki@chromium.org
Notry: true
Reviewed-on: https://chromium-review.googlesource.com/c/1420514
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Commit-Queue: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624030}
1 file changed