Details:
- Extend ElementAccessors with GetAttributes method.
- Add HasLocalElement, Get[Local]ElementAttribute methods to JSReceiver/JSObject.
- Otherwise, mirror implementation for named properties.

Cannot correctly handle the cases yet where an accessor is redefined or deleted.

Also fixed handling of object info table.

(Based on CL https://codereview.chromium.org/11362115/)

R=verwaest@chromium.org,mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/11365111

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12900 ce2b1a6d-e550-0410-aec6-3dcde31c8c00