btrfs/030: add more test cases

btrfs/030: add more test cases

This change adds some new tests for btrfs' incremental send feature.
These are all related with inverting the parent-child relationship
of directories, and cover the cases:

* when the new parent didn't get renamed (just moved)
* when a child file of the former parent gets renamed too

These new cases are fixed by the following btrfs linux kernel patches:

* "Btrfs: more send support for parent/child dir relationship inversion"
* "Btrfs: fix send dealing with file renames and directory moves"

Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>