Disable external/wpt/css/css-fonts/inheritance.html on Mac

Tbr: ericwilligers@chromium.org
Bug: 966249
Change-Id: I06f2daae2e0b1bcacb50e9223ae9657e69d34e6a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1692237
Commit-Queue: Kevin McNee <mcnee@chromium.org>
Reviewed-by: Kevin McNee <mcnee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#675754}

third_party/blink/web_tests/TestExpectations

@@ -6263,3 +6263,6 @@ crbug.com/982289 virtual/gpu-rasterization/images/color-profile-image-canvas-pat
 crbug.com/982289 virtual/gpu-rasterization/images/color-profile-image-canvas.html [ Pass Failure ]
 crbug.com/982289 virtual/gpu-rasterization/images/color-profile-mask-image-svg.html [ Pass Failure ]
 crbug.com/982289 virtual/gpu-rasterization/images/ycbcr-with-cmyk-color-profile.html [ Pass Failure ]
+
+# Sheriff 2019-07-09
+crbug.com/966249 [ Mac ] external/wpt/css/css-fonts/inheritance.html [ Pass Failure ]