Mark RTCPeerConnection-track-stats.https.html as timing out on all the platforms

TBR=hbos@chromium.org

Bug: 829401
Change-Id: I98b7d3149599e876d673a84718215521ddf6cfac
Reviewed-on: https://chromium-review.googlesource.com/1004995Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Commit-Queue: Vasilii Sukhanov <vasilii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549485}

third_party/WebKit/LayoutTests/TestExpectations

@@ -2660,7 +2660,7 @@ crbug.com/626703 external/wpt/webaudio/the-audio-api/the-mediaelementaudiosource
 crbug.com/626703 external/wpt/webrtc/RTCPeerConnection-setLocalDescription-rollback.html [ Timeout ]
 crbug.com/626703 external/wpt/webrtc/RTCPeerConnection-setRemoteDescription.html [ Timeout ]
 crbug.com/626703 external/wpt/webrtc/RTCPeerConnection-setRemoteDescription-rollback.html [ Timeout ]
-crbug.com/829401 [ Win ] external/wpt/webrtc/RTCPeerConnection-track-stats.https.html [ Pass Timeout ]
+crbug.com/829401 external/wpt/webrtc/RTCPeerConnection-track-stats.https.html [ Pass Timeout ]
 crbug.com/626703 external/wpt/webvtt/rendering/cues-with-video/processing-model/2_cues_overlapping_completely_move_up.html [ Failure ]
 crbug.com/626703 external/wpt/webvtt/rendering/cues-with-video/processing-model/2_cues_overlapping_partially_move_down.html [ Failure ]
 crbug.com/626703 external/wpt/webvtt/rendering/cues-with-video/processing-model/2_cues_overlapping_partially_move_up.html [ Failure ]