Update TestExpectation for snap-to-area-with-fractional-offset.html

The test was flaky on Mac 10.13 due to Timeout rather than Failure.
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_layout_tests%20(with%20patch)&tests=virtual/threaded/fast/scroll-snap/snap-to-area-with-fractional-offset.html

Bug: 1036054
Change-Id: I497b3bb58fc15fd29be0608f6be3326dd7085e13
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1986767Reviewed-by: Xida Chen <xidachen@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#728193}

third_party/blink/web_tests/TestExpectations

@@ -6133,7 +6133,7 @@ crbug.com/859169 http/tests/devtools/layers/layer-compositing-reasons.js [ Pass
 # Sheriff 2019-12-23
 crbug.com/1036626 http/tests/devtools/tracing/tracing-record-input-events.js [ Pass Failure ]
 crbug.com/1036626 virtual/threaded/http/tests/devtools/tracing/tracing-record-input-events.js [ Pass Failure ]
-crbug.com/1036054 [ Mac10.13 ] virtual/threaded/fast/scroll-snap/snap-to-area-with-fractional-offset.html [ Pass Failure ]
+crbug.com/1036054 [ Mac10.13 ] virtual/threaded/fast/scroll-snap/snap-to-area-with-fractional-offset.html [ Pass Timeout ]
 crbug.com/960944 animations/web-animations/animation-state-changes-positive-playback-rate.html [ Pass Failure ]
 crbug.com/1033381 synthetic_gestures/smooth-scroll-tiny-delta.html [ Pass Crash ]