Remove crash tests expectation for video-decoder.html

Crash fixed by:
https://chromium.googlesource.com/chromium/src.git/+/39bb8526f08be06a5d19791cc0fc98a5978dedd0

Bug: 1121015, 1120431
Change-Id: I957909c539d4c626dbeb238fd7e856bce4fcebb1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2373174Reviewed-by: Dan Sanders <sandersd@chromium.org>
Commit-Queue: Dan Sanders <sandersd@chromium.org>
Commit-Queue: Chrome Cunningham <chcunningham@chromium.org>
Auto-Submit: Chrome Cunningham <chcunningham@chromium.org>
Cr-Commit-Position: refs/heads/master@{#801159}

third_party/blink/web_tests/TestExpectations

@@ -6708,7 +6708,4 @@ crbug.com/1117613 media/video-error-networkState.html [ Failure Timeout ]
 # Sheriff 2020-0-21
 crbug.com/1120330 virtual/threaded/external/wpt/feature-policy/experimental-features/vertical-scroll-disabled-scrollbar-tentative.html [ Pass Failure ]
 
-# Sheriff 2020-08-24
-crbug.com/1121015 [ Linux ] external/wpt/webcodecs/video-decoder.html [ Pass Crash ]
-
 crbug.com/1119676 external/wpt/html/cross-origin-embedder-policy/reporting-to-endpoint.https.html [ Failure ]