Fixed issue 619 allowing Object.create to be called with a function.

Fixed issue 619 allowing Object.create to be called with a function.

This change allows Object.create to take a function as input in the
proto argument. The spec says that Type(O) for the proto argument
should be true but our IS_OBJECT does not check for this. I will make a
IS_SPEC_OBJECT in macros.py and refactor v8natives in another CL.

Review URL: http://codereview.chromium.org/2051001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4622 ce2b1a6d-e550-0410-aec6-3dcde31c8c00