Revert addition of raw literals to the parsetree

It turns out it is not possible to have the exact raw representation
since a constant does not always correspond to exactly one token, so
there is no point in making the AST more complex.


git-svn-id: http://caml.inria.fr/svn/ocaml/branches/extension_points@13702 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02