zdtm: Add a test to check if we can C/R ghost files with no parent dirs.

This is test that triggers a bug with ghost files, that was resolved in
patch "Don't fail if ghost file has no parent dirs".

Signed-off-by: Vitaly Ostrosablin <vostrosablin@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>