Support for inlined records in extension constructors.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/constructors_with_record4@15375 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Re-enable rebinding of extension constructors with inlined records.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/constructors_with_record4@15376 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
No need to track extension path in record_representation, infer it from the result type of the label.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/constructors_with_record4@15377 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02