gardening: svg/custom/foreign-object-skew.svg fails on Mac

BUG=390488
TBR=pilgrim@chromium.org

Review URL: https://codereview.chromium.org/364533003

git-svn-id: svn://svn.chromium.org/blink/trunk@177294 bbb929c8-8fbe-4397-9dbb-9b2b20218538