PR#5774: Add test for the bswap primitives.

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13204 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
PR#5774: Updates Changes.

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13205 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02