Restored some shape-outside tests.

This patch restores some of the shape-outside tests that had been temporarily
removed when the positioning model was changed.

BUG=269557

Review URL: https://chromiumcodereview.appspot.com/22616004

git-svn-id: svn://svn.chromium.org/blink/trunk@155766 bbb929c8-8fbe-4397-9dbb-9b2b20218538