Disable media/controls/volumechange-muted-attribute.html for flakiness

Tbr: mlamouri@chromium.org
Bug: 1083302
Change-Id: I738e4a7188e32b94261f12e457fed4f7c2bb5c1c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2285346Reviewed-by: Kevin McNee <mcnee@chromium.org>
Commit-Queue: Kevin McNee <mcnee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#786006}

third_party/blink/web_tests/TestExpectations

@@ -5939,7 +5939,6 @@ crbug.com/994692 [ Win ] compositing/reflections/nested-reflection-anchor-point.
 # Video flakily not being being rendered on Mac
 crbug.com/988248 media/controls/captions-menu-always-visible.html [ Pass Failure ]
 crbug.com/988248 [ Mac ] media/controls/overflow-menu-always-visible.html [ Pass Failure ]
-crbug.com/988248 [ Mac ] media/controls/volumechange-muted-attribute.html [ Pass Failure ]
 crbug.com/988248 [ Mac ] media/video-persistence.html [ Pass Failure ]
 crbug.com/988248 [ Linux ] media/video-persistence.html [ Pass Failure ]
 crbug.com/988248 [ Mac ] media/video-zoom.html [ Pass Failure ]
@@ -6794,3 +6793,7 @@ crbug.com/1100786 [ Mac10.10 ] storage/indexeddb/transaction-active-flag.html [
 crbug.com/1101699 external/wpt/webrtc/RTCPeerConnection-setLocalDescription-answer.html [ Pass Failure ]
 crbug.com/1101699 external/wpt/webrtc/RTCPeerConnection-setLocalDescription-pranswer.html [ Pass Failure ]
 crbug.com/1101699 virtual/webrtc-wpt-plan-b/external/wpt/webrtc/RTCPeerConnection-setRemoteDescription-rollback.html [ Pass Failure ]
+
+# Sheriff 2020-07-07
+# Additionally disabled on mac due to crbug.com/988248
+crbug.com/1083302 media/controls/volumechange-muted-attribute.html [ Pass Failure ]