Handle JavaScript accessors on the global object.

Handle JavaScript accessors on the global object.

With the new representation of the global object adding JavaScript accessors for a property after global inline caches was created for that property did not work property as the inline caches did not take the JavaScript accessor information (fixed array with two elements) that could be present in a global object property cell into account.

This is now fixed by changing the map for a global object when a JavaScript accessor is defined on it.

BUG=394
TEST=test\mjsunit\regress\regress-394.js
Review URL: http://codereview.chromium.org/150162

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2317 ce2b1a6d-e550-0410-aec6-3dcde31c8c00