This is a first step towards loading globals directly from property cells instead
of going through a load IC.

This change supports only properties with the DontDelete attribute since
we are only able to bailout into the generic code generated by the secondary 
code generator the beginning of a function. The resulting fast-case code is 
specialized for a specific context. When invoked with a different global object, 
it will always bailout to the secondary code.

When loading a property that does not exist at compile-time or a property
that is deleteable we still generate the generic load IC.

Review URL: http://codereview.chromium.org/565034

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3808 ce2b1a6d-e550-0410-aec6-3dcde31c8c00