[BlinkGenPropertyTrees] Add missed fixed test

It appears this was missed in https://chromium-review.googlesource.com/1091504
because it was listed separately.

TBR=flackr@chromium.org
BUG=762717

Change-Id: Id0fce202ec87376003b96e448c22f3e9ed7e0de2
Reviewed-on: https://chromium-review.googlesource.com/1113500Reviewed-by: Peter Mayo <petermayo@chromium.org>
Commit-Queue: Peter Mayo <petermayo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570054}

third_party/WebKit/LayoutTests/FlagExpectations/enable-blink-gen-property-trees

@@ -422,7 +422,6 @@ Bug(none) virtual/threaded/fast/scrolling/doc-write-to-iframe.html [ Crash Failu
 Bug(none) fast/events/drag-and-drop-dataTransfer-types-nocrash.html [ Failure Pass ]
 Bug(none) fast/events/onchange-textfield.html [ Failure Pass ]
 Bug(none) fast/events/pointerevents/mouse-pointer-chorded-buttons.html [ Failure Pass ]
-Bug(none) virtual/threaded/fast/animationworklet/animation-worklet-scroll-timeline-dispose.html [ Crash Failure Pass ]
 Bug(none) virtual/threaded/fast/scrolling/hide-scrollbars.html [ Crash Failure Pass ]
 Bug(none) virtual/threaded/fast/scrolling/scrollbar-mousedown-move-mouseup.html [ Failure Pass ]
 Bug(none) virtual/threaded/fast/scrolling/scrollbar-prevent-default.html [ Crash Failure Pass ]