btrfs: test incremental send after deleting directories with many hardlinks

Test that an incremental send works after we removed directories that have
large number of hardlinks for the same file (so that we have extrefs).

This is a regression test for the kernel commit 1fabe43b4e1a ("btrfs:
send: fix duplicated rmdir operations when using extrefs").

Signed-off-by: Filipe Manana <[email protected]>
Signed-off-by: Zorro Lang <[email protected]>
2 files changed