Mark http/tests/xmlhttprequest/ontimeout-event-override-after-failure.html as flaky (again).

This was previously marked, and is still flaky:
  http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=http%2Ftests%2Fxmlhttprequest%2Fontimeout-event-override-after-failure.html

This line was removed earlier here:
  https://codereview.chromium.org/1259743005

BUG=464736
[email protected],[email protected]
NOTRY=true

Review URL: https://codereview.chromium.org/1355003004

git-svn-id: svn://svn.chromium.org/blink/trunk@202636 bbb929c8-8fbe-4397-9dbb-9b2b20218538
diff --git a/third_party/WebKit/LayoutTests/TestExpectations b/third_party/WebKit/LayoutTests/TestExpectations
index 5a71e98..450ad737 100644
--- a/third_party/WebKit/LayoutTests/TestExpectations
+++ b/third_party/WebKit/LayoutTests/TestExpectations
@@ -1227,6 +1227,8 @@
 crbug.com/528431 paint/invalidation/spv2/fixed-img-src-change-after-scroll.html [ Skip ]
 crbug.com/528431 paint/invalidation/spv2/background-image-paint-invalidation.html [ Skip ]
 
+crbug.com/464736 http/tests/xmlhttprequest/ontimeout-event-override-after-failure.html [ Pass Failure ]
+
 # Unclear semantics of ToString (actually ToPrimitive) across iframes.
 crbug.com/532469 http/tests/security/cross-frame-access-custom.html [ NeedsManualRebaseline ]