xfs/132: remove duplicate test

xfs/132: remove duplicate test

Test description says: "This is the same test as generic/156 except
that we also check the inode reflink flag.", only since commit
f1c3fee ("xfs: remove NOCOW_FL testing from test") it is almost
exactly the same test as generic/156.
almost - because since xfs/132 diverged from generic/156 the change
911efb0 ("reflink: change to relative margins") is only applied to
the original test.

Anyway, there doesn't seem to be a reason to keep this duplicated
test anymore, so remove it.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>