Mark large-list-of-rules-crash.html as Slow.

Bug: 973726, 1092121
Change-Id: I38a66a3584845bc982e2a993fc8197c6fcfdeb45
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2235672Reviewed-by: Stephen Chenney <schenney@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#776045}

third_party/blink/web_tests/SlowTests

@@ -534,3 +534,4 @@ crbug.com/1091716 svg/as-object/sizing/svg-in-object-placeholder-percentage-perc
 crbug.com/1091716 svg/as-object/sizing/svg-in-object-placeholder-percentage-percentage-no-intrinsic-ratio.html [ Slow ]
 
 crbug.com/1043669 [ Mac ] inspector-protocol/emulation/set-vision-deficiency.js [ Slow ]
+crbug.com/1092121 fast/css/large-list-of-rules-crash.html [ Slow ]

third_party/blink/web_tests/TestExpectations

@@ -5847,7 +5847,6 @@ crbug.com/971319 [ Mac ] media/audio-garbage-collect.html [ Pass Timeout ]
 
 # Sheriff 2019-06-13
 crbug.com/973692 [ Mac ] external/wpt/css/css-text/parsing/hyphens-computed.html [ Failure ]
-crbug.com/973726 [ Mac ] fast/css/large-list-of-rules-crash.html [ Pass Timeout ]
 
 # Sheriff 2019-06-20
 crbug.com/976045 fast/scrolling/unscrollable-layer-subpixel-size-with-negative-overflow.html [ Pass Failure ]