cloneNode: Change the default value back to false

We used to use false as the default value for cloneNode. It was
recently changed to default to true to match the DOM spec. However, the
DOM spec was changed back to use false as the default value.

This should be safe because until recently Firefox threw exceptions
if no argument was passed. IE11, WebKit, Presto and Chrome
(before r153733, July) uses false as the default.

BUG=309628
R=esprehn@chromium.org

Review URL: https://codereview.chromium.org/33083002

git-svn-id: svn://svn.chromium.org/blink/trunk@160136 bbb929c8-8fbe-4397-9dbb-9b2b20218538