[GStreamer] gardening a couple crashing tests

https://bugs.webkit.org/show_bug.cgi?id=271699

Unreviewed, flag a couple tests as crashing until the PR in bug 271517 is reviewed and landed...

* LayoutTests/platform/glib/TestExpectations:

Canonical link: https://commits.webkit.org/276680@main

LayoutTests/platform/glib/TestExpectations

@@ -2028,7 +2028,8 @@ webkit.org/b/235885 webrtc/ephemeral-certificates-and-cnames.html [ Failure ]
 webkit.org/b/235885 webrtc/filtering-ice-candidate-after-reload.html [ Failure ]
 webkit.org/b/235885 webrtc/peer-connection-track-end.html [ Failure ]
 webkit.org/b/235885 webrtc/peerconnection-page-cache.html [ Timeout ]
-webkit.org/b/235885 webrtc/video-stats.html [ Failure ]
+webkit.org/b/271517 webrtc/video-stats.html [ Crash ]
+#webkit.org/b/235885 webrtc/video-stats.html [ Failure ]
 webkit.org/b/235885 webrtc/vp8-then-h264.html [ Failure Timeout Crash ]
 webkit.org/b/252878 fast/mediastream/mediastreamtrack-video-clone.html [ Crash Failure Timeout Pass ]
 webkit.org/b/213202 fast/mediastream/getUserMedia-grant-persistency3.html [ Failure Pass ]
@@ -2048,7 +2049,8 @@ webrtc/captureCanvas-webrtc.html [ Pass Timeout ]
 webkit.org/b/252878 webrtc/audio-peer-connection-webaudio.html [ Failure Pass Timeout ]
 webkit.org/b/252878 webrtc/audio-samplerate-change.html [ Pass Timeout ]
 webkit.org/b/252878 webrtc/datachannel/bufferedAmountLowThreshold-default.html [ Failure Pass ]
-webkit.org/b/252878 webrtc/video-h264.html [ Pass Timeout ]
+webkit.org/b/271517 webrtc/video-h264.html [ Crash ]
+#webkit.org/b/252878 webrtc/video-h264.html [ Pass Timeout ]
 
 imported/w3c/web-platform-tests/mediacapture-streams/GUM-required-constraint-with-ideal-value.https.html [ Pass Failure ]
 imported/w3c/web-platform-tests/mediacapture-streams/MediaStream-MediaElement-preload-none.https.html [ Pass Failure ]