btrfs: test newly supported cases of cloning inline extents

btrfs: test newly supported cases of cloning inline extents

Test several scenarios of cloning operations where the source range
includes inline extents. They used to not be supported on btrfs
because their implementation was not straightforward, and therefore
these operations used to fail with errno EOPNOTSUPP on older
kernels.

This currently fails on any released kernel. It passes only when the
patch with the following subject is applied:

  "Btrfs: implement full reflink support for inline extents"

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>