Mark video-surface-layer's text-track-menu-pointer-selection.html flaky.

NOTRY=true (disabling test)

Bug: 876050
TBR: mlamouri@chromium.org
Change-Id: I194461ae3a8ca045dd0b9201331c191bc644ec5b
Reviewed-on: https://chromium-review.googlesource.com/1182293Reviewed-by: apacible <apacible@chromium.org>
Commit-Queue: apacible <apacible@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584561}

third_party/WebKit/LayoutTests/TestExpectations

@@ -268,6 +268,7 @@ crbug.com/417223 external/wpt/css/css-position/position-relative-table-tr-top.ht
 crbug.com/722825 media/controls/video-enter-exit-fullscreen-while-hovering-shows-controls.html [ Timeout Pass ]
 crbug.com/722825 virtual/new-remote-playback-pipeline/media/controls/video-enter-exit-fullscreen-while-hovering-shows-controls.html [ Timeout Pass ]
 crbug.com/722825 virtual/video-surface-layer/media/controls/video-enter-exit-fullscreen-while-hovering-shows-controls.html [ Timeout Pass ]
+crbug.com/876050 virtual/video-surface-layer/media/controls/text-track-menu-pointer-selection.html [ Pass Failure ]
 
 #### crbug.com/783229 overflow
 crbug.com/724701 overflow/overflow-basic-004.html [ Failure ]