[Sheriff] Added test as flaky in all platforms

Change-Id: Ie023a5d635de0c976033d7f510a2a0f7bb9ca72e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1018027
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1890330Reviewed-by: Kamila Hasanbega <hkamila@google.com>
Reviewed-by: Kamila Hasanbega <hkamila@chromium.org>
Commit-Queue: Kamila Hasanbega <hkamila@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710735}

third_party/blink/web_tests/TestExpectations

@@ -5744,6 +5744,9 @@ crbug.com/1018027 virtual/threaded-no-composited-antialiasing/animations/custom-
 crbug.com/1018027 virtual/threaded-no-composited-antialiasing/animations/custom-properties/registered-var-to-unregistered-animating.html [ Pass Crash ]
 crbug.com/1018064 [ Mac10.13 ] virtual/threaded/http/tests/devtools/tracing/timeline-js/timeline-js-line-level-profile-end-to-end.js [ Pass Timeout ]
 
+# Sheriff 2019-10-30
+crbug.com/1018027 virtual/threaded-no-composited-antialiasing/animations/custom-properties/registered-var-to-registered.html [ Pass Crash ]
+
 # Temporarily disabled for landing coverage changes in DevTools
 crbug.com/1009396 http/tests/devtools/coverage/coverage-export.js [ Pass Failure ]
 crbug.com/1009396 http/tests/devtools/coverage/coverage-repeated.js [ Pass Failure ]