The layout test animations/fill-mode-forwards.html is flaky on platform GTK.
Before r171725 <http://trac.webkit.org/changeset/171725> it was timing out sometimes (like 10% of the times).
After r171725 it times out most of the times and also crashes sometimes
The same happens with animations/animation-matrix-negative-scale-unmatrix.html
It was timing out sometimes (~10%) before r171725.
After r171725 it fails or timeouts most of the times.
When it fails, the diff is: http://build.webkit.org/results/GTK%20Linux%2064-bit%20Release%20%28Tests%29/r171725%20%281749%29/animations/animation-matrix-negative-scale-unmatrix-pretty-diff.html
Updated the GTK TestExpectations on http://trac.webkit.org/changeset/171963 for this failures