[V8] Simplify CodeGeneratorV8.pm by using InheritsExtendedAttribute("EventTarget")
https://bugs.webkit.org/show_bug.cgi?id=108441

Reviewed by Adam Barth.

A complicated condition in GetInternalFields() can be simplified
by using InheritsExtendedAttribute("EventTarget").

No tests. No change in behavior.

* bindings/scripts/CodeGeneratorV8.pm:
(GetInternalFields):
* dom/EventTarget.idl: Added [EventTarget] which should have been added.
* svg/SVGElementInstance.idl: Ditto.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141502 268f45cc-cd09-0410-ab3c-d52691b4dbfc