[Sheriff] Mark one test as failure on Mac and Linux

external/wpt/html/canvas/offscreen/manual/the-offscreen-canvas/offscreencanvas.resize.html
is failing after http://crrev.com/777259.

TBR=aaronhk@chromium.org

No-Try: true
Bug: 1093709,1091267
Change-Id: Ifc285409dd7c1f014d0c8450ace0ccfb538ba3c3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2241052Reviewed-by: Kunihiko Sakamoto <ksakamoto@chromium.org>
Commit-Queue: Kunihiko Sakamoto <ksakamoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#777283}

third_party/blink/web_tests/TestExpectations

@@ -6728,3 +6728,5 @@ crbug.com/1093003 [ Mac ] external/wpt/html/rendering/replaced-elements/embedded
 # Sheriff 2020-06-10
 crbug.com/1093429 [ Mac ] external/wpt/webrtc/RTCPeerConnection-getStats.https.html [ Failure ]
 crbug.com/1093620 [ Debug ] http/tests/devtools/appcache/* [ Pass Failure ]
+crbug.com/1093709 [ Mac ] external/wpt/html/canvas/offscreen/manual/the-offscreen-canvas/offscreencanvas.resize.html [ Pass Failure ]
+crbug.com/1093709 [ Linux ] external/wpt/html/canvas/offscreen/manual/the-offscreen-canvas/offscreencanvas.resize.html [ Pass Failure ]