inspector-protocol/animation/animation-multiple-frames.js is flaky.

BUG=856955
TBR=grt@chromium.org

Change-Id: I3dc85cc564100b27fc4c3cd2a584952c48dfb981
Reviewed-on: https://chromium-review.googlesource.com/1116550Reviewed-by: Greg Thompson <grt@chromium.org>
Commit-Queue: Greg Thompson <grt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570717}

third_party/WebKit/LayoutTests/TestExpectations

@@ -4733,3 +4733,6 @@ crbug.com/856601 [ Linux ] external/wpt/presentation-api/controlling-ua/idlharne
 crbug.com/856601 [ Linux ] fast/css/visited-link-hang.html [ Pass Timeout ]
 crbug.com/856601 [ Linux ] http/tests/devtools/elements/styles-4/styles-inline-element-style-changes-should-not-force-style-recalc.js [ Pass Timeout ]
 crbug.com/856601 [ Linux ] virtual/feature-policy-permissions/external/wpt/mediacapture-streams/MediaDevices-IDL-enumerateDevices.html [ Pass Timeout ]
+
+# Sheriff 2018-06-27
+crbug.com/856955 [ Win10 Linux ] inspector-protocol/animation/animation-multiple-frames.js [ Failure Pass ]