Convert some layout tests to text-based-repaint tests

- less code
- able to use features of text-based-repaint.js

Review URL: https://codereview.chromium.org/403843002

git-svn-id: svn://svn.chromium.org/blink/trunk@178496 bbb929c8-8fbe-4397-9dbb-9b2b20218538