xfs: test xfsrestore on multi-level dumpfiles with wrong root

xfs: test xfsrestore on multi-level dumpfiles with wrong root

While developing `xfsrestore -x`, we hit an issue at restoring a
renamed file in the cumulative mode (multi-level dumps):
  https://lore.kernel.org/linux-xfs/e61ae295-a331-d36a-cae1-646022dc2a6e@gmail.com/
Then, this patch adds test cases where '-x' flag is used in the
cumulative mode with various file operations referring to existing tests.

Signed-off-by: Hironori Shiina <shiina.hironori@fujitsu.com>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>