Convert fast/multicol/column-count-with-rules (and related) to reftests.

 * Make test small enough to fit in content_shell. (Only the baselines for
   the -webkit-writing-mode versions were incorrect, though).
 * Used explicit column-gap to simplify ref.
 * Used even-size column-rule to simplify ref.

R=mstensho@opera.com
BUG=386567

Review URL: https://codereview.chromium.org/670473002

git-svn-id: svn://svn.chromium.org/blink/trunk@184202 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: text node rendering in the console regressed when migrated to promises.

Review URL: https://codereview.chromium.org/654753003

git-svn-id: svn://svn.chromium.org/blink/trunk@184203 bbb929c8-8fbe-4397-9dbb-9b2b20218538