testsuite: simplification of the BYTECODE_ONLY macro

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13672 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
testsuite/lib-threads: stop all threads before exiting [for Windows]

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13673 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02