Sheriff: Disable a flaky test

Bug: 1064839
Change-Id: I4cd3997de437270ecfcdb45f5d6dfa01618ffd8d
TBR: davve@opera.com
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2123495Reviewed-by: Hayato Ito <hayato@chromium.org>
Commit-Queue: Hayato Ito <hayato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#753935}

third_party/blink/web_tests/TestExpectations

@@ -6676,3 +6676,5 @@ crbug.com/1064463 external/wpt/web-animations/interfaces/Animation/style-change-
 
 # Sheriff 2020-03-26
 crbug.com/1064839 fast/hidpi/image-srcset-svg-canvas-2x.html [ Pass Failure ]
+# Sheriff 2020-03-27
+crbug.com/1064839 fast/hidpi/image-srcset-svg-canvas.html [ Pass Failure ]