LU-16334 llite: update statx size/ctime for fallocate

LU-16334 llite: update statx size/ctime for fallocate

In the VFS interface ->fallocate(), it should update i_size and
i_ctime returned by statx() accordingly when the file size grows.

Add sanity/150h.

fallocate() call does not update the attributes on MDT.
We use STATX with cached-always mode to verify it as it will not
send Glimpse lock RPCs to OSTs to obtain file size information
and use the caching attributes (size) on the client side as much
as possible.

Signed-off-by: Qian Yingjin <qian@ddn.com>
Change-Id: Ib8128892222a01cd00250c704328bd13cfb12e2d
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/49221
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>