xfstests: improve test 286 for repeated unwritten/hole extents.

xfstests: improve test 286 for repeated unwritten/hole extents.

Enlarge the test coverage of 286 to includes file mapping with repeated
hole/unwritten/unwritten_without_data/data intersections.

Those two new sub-tests could help verifying the current seek_data/seek_hole
improvements.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mark Tinguely <tinguely@sgi.com>
 286 |   87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 86 insertions(+), 1 deletion(-)