xfs/166: fix golden output failures when multipage folios enabled

xfs/166: fix golden output failures when multipage folios enabled

Beginning with 5.18, some filesystems support creating large folios for
the page cache.  A system with 64k pages can create 256k folios, which
means that with the old file size of 1M, the last half of the file is
completely converted from unwritten to written by page_mkwrite.  The
test encodes a translated version of the xfs_bmap output in the golden
output, which means that the test now fails on 64k pages.  Fixing the
64k page case by increasing the file size to 2MB broke fsdax because
fsdax uses 2MB PMDs, hence 12MB.

Increase the size to prevent this from happening.  This may require
further revision if folios get larger or fsdax starts supporting PMDs
that are larger than 2MB.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>