Gardening: virtual/threaded/animations/missing-keyframe-properties.html

It times out on linux from time to time

BUG=248938
TEST=
TBR=zmo@chromium.org

Review URL: https://codereview.chromium.org/203983003

git-svn-id: svn://svn.chromium.org/blink/trunk@169481 bbb929c8-8fbe-4397-9dbb-9b2b20218538