Update inheritance hierarchy in Objects.h to better reflect the actual hierarchy.

Update inheritance hierarchy in Objects.h to better reflect the actual hierarchy.

We do not have a GlobalContext class.

We do, however, have a SerializedScopeInfo class that inherits FixedArray.

Starting comment is also slightly misleading, since not all objects in the hierarchy is described in objects.h (e.g., Context is described in contexts.h).

Review URL: http://codereview.chromium.org/2811057

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5101 ce2b1a6d-e550-0410-aec6-3dcde31c8c00