tests: fix 'invalid path dir' error On OS/2, a path separator is ';' not ':'. And ':' is used as a separator between a drive letter and directory parts. As a result, an absolute path such as x:/path/to/dir on OS/2 is treated as an invalid path dir. * tests/init.sh (PATH_SEPARATOR): Set at startup. (path_prepend_): '?:*' is also an absolute path. Use $PATH_SEPARATOR instead of hard coded ':'.