svg/animations/animateMotion-additive-2b.svg frequently fails on Mavericks WebKit2 with a single pixel difference. http://webkit-test-results.appspot.com/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=svg%2Fanimations%2FanimateMotion-additive-2b.svg http://build.webkit.org/results/Apple%20Mavericks%20Debug%20WK2%20(Tests)/r161123%20(1247)/svg/animations/animateMotion-additive-2b-diff.png