Fix test failure from the previous check-in.

* fast/dynamic/window-resize-scrollbars-test.html: Add resize handler so this test works
with asynchronous resizing.

* platform/wk2/TestExpectations: Expect failure for the test above; it's showing scrollbars,
and it should not. Before, the test was not running correctly so it seemed to pass.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@169508 268f45cc-cd09-0410-ab3c-d52691b4dbfc