btrfs-progs: fsck-tests: make test case 066 to be repairable

The test case fsck/066 is only to verify we can detect the missing root
orphan item, no repair for it yet.

Now the repair ability is added, change the test case to verify the
repair is also properly done.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>

Author: adam900710