Generate better isFooElement() helper functions for HTML Elements

Generate better isFooElement() helper functions for HTML Elements. Specialize
HTML element type checking helpers to only compare the localName and not the
fully qualified tag name as this is sufficient and a little bit faster.

This is based on the following WebKit revision by <akling@apple.com>:
http://trac.webkit.org/changeset/157343

R=esprehn, adamk, eseidel
BUG=346095

Review URL: https://codereview.chromium.org/195993009

git-svn-id: svn://svn.chromium.org/blink/trunk@169187 bbb929c8-8fbe-4397-9dbb-9b2b20218538