make the testsuite work on cygwin-64, where dynamic linking is not yet available

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14336 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
port to cygwin-64

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14337 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02