Split compositing/repaint/should-not-repaint-*.html into smaller tests

The original tests each contain multiple tests making the results
hard to read.

Split them into smaller tests and convert them into text based
repaint tests.

Review URL: https://codereview.chromium.org/390933004

git-svn-id: svn://svn.chromium.org/blink/trunk@178107 bbb929c8-8fbe-4397-9dbb-9b2b20218538