[Sheriff] Disable fast/test/small-caps-aat.html

The small-caps-aat.html was failing on the WebKit Mac10.13 (retina)
builder.

Tbr: drott@chromium.org
Bug: 910263
Change-Id: Idbe95ab8055f53b777c03c7e6a5d283abf691074
Reviewed-on: https://chromium-review.googlesource.com/c/1359063Reviewed-by: Ovidio Henriquez <odejesush@chromium.org>
Commit-Queue: Ovidio Henriquez <odejesush@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613249}

third_party/blink/web_tests/TestExpectations

@@ -5754,6 +5754,8 @@ crbug.com/910263 [ Mac ] fast/block/float/016.html [ Pass Crash Failure ]
 crbug.com/910263 [ Mac ] fast/text/international/complex-character-based-fallback.html [ Pass Crash Failure ]
 crbug.com/910263 [ Mac ] fonts/cursive.html [ Pass Crash Failure ]
 crbug.com/910263 [ Mac ] svg/text/ligature-queries.html [ Pass Crash Failure ]
+# Sheriff 2018-12-03
+crbug.com/910263 [ Mac ] fast/text/small-caps-aat.html [ Pass Crash Failure ]
 
 #Sheriff 2018-12-03
 crbug.com/910846 [ Win ] virtual/streaming-preload/external/wpt/html/semantics/scripting-1/the-script-element/execution-timing/078.html [ Failure Pass Timeout ]