Remove several unused Node methods

Remove several unused Node methods that merely call the corresponding implementation
in Element:
- hasLocalName()
- hasAttributes()
- attributes()

R=eseidel
BUG=

Review URL: https://codereview.chromium.org/26678003

git-svn-id: svn://svn.chromium.org/blink/trunk@159344 bbb929c8-8fbe-4397-9dbb-9b2b20218538