generic/{102,172,347}: Adapt test for XFS on systems with 128+CPUs + SSDs

generic/{102,172,347}: Adapt test for XFS on systems with 128+CPUs + SSDs

XFS will now scale by default its log size according the amount of CPUs. This
can significantly increase the log area and using hard-coded size of file size
will make the test file. Using the X percent of the free space to create the
file will let the test proceed.

For generic/102 we also have to change the 102.out as we cannot know the
amount written data and it has to be filtered out.

For generic/172 we just use the new function to calculate file big enough
to consume most of the available space.

The generic/347 will use -l concurrency=0 in case it is being run on the
XFS filesystem and mkfs.xfs already supports this option.

Signed-off-by: Lukas Herbolt <lukas@herbolt.com>
Reviewed-by: Zorro Lang <zlang@kernel.org>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>