Add a layout test for the crash on infinite loop in SVG textPath.

The reported crash can't be reproduced anymore.

BUG=232903

Review URL: https://codereview.chromium.org/180213005

git-svn-id: svn://svn.chromium.org/blink/trunk@168330 bbb929c8-8fbe-4397-9dbb-9b2b20218538