Revert r160161 "Enable animation for the shape-margin property"

Introduces failing test: http://test-results.appspot.com/dashboards/flakiness_dashboard.html#group=%40ToT%20Blink&tests=animations/interpolation/webkit-shape-margin.html

BUG=

Review URL: https://codereview.chromium.org/34483005

git-svn-id: svn://svn.chromium.org/blink/trunk@160207 bbb929c8-8fbe-4397-9dbb-9b2b20218538