zdtm: add posix file lock's test case

We check read lock and write lock for posix file locks. After restore,
we use fcntl(fd, F_GETLK, &lock), to see if the file is hold the same
lock as it was dumped.

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>