DevTools: Do not provide @href for anchors with the javascript: scheme

Linkified javascript: URLs in the DOM tree should not be navigable at all

R=eustas, pfeldman, vsevik
BUG=344352

Review URL: https://codereview.chromium.org/169913002

git-svn-id: svn://svn.chromium.org/blink/trunk@167309 bbb929c8-8fbe-4397-9dbb-9b2b20218538