[CSS Shapes] Add performance tests

Add various performance tests for CSS Shapes taken from
https://bugs.webkit.org/show_bug.cgi?id=128188.

BUG=349093
NOTRY=true

Review URL: https://codereview.chromium.org/186783003

git-svn-id: svn://svn.chromium.org/blink/trunk@168525 bbb929c8-8fbe-4397-9dbb-9b2b20218538