Do not keep explicit datasize with immediate integer operands.  Special support for movabsq.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/abstract_intel_emit@15291 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Cleanup.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/abstract_intel_emit@15292 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02