Fixed Object::clone, did not tolerate object movement.
Fixed Object::clone, did not tolerate object movement.

Uncovers general problem of ``this`` in Object. It can be
outdated/invalidated by object movement.
Fix done by David.

smarr/OmniVM,smarr/OmniVM,smarr/OmniVM,smarr/OmniVM,smarr/OmniVM,smarr/OmniVM,smarr/OmniVM,smarr/OmniVM