torture/ioctl: add simple FSCTL_FILE_LEVEL_TRIM test

torture/ioctl: add simple FSCTL_FILE_LEVEL_TRIM test

This test writes out a 128K file and then attempts to trim the first
half of the file. Trim support is first detected using an
FS_SECTOR_SIZE_INFORMATION query-info request. If the server doesn't
support trim, then the test is skipped.

Signed-off-by: David Disseldorp <ddiss@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Wed Mar 18 21:32:47 CET 2015 on sn-devel-104