Hi,

Like (almost) all GC related tests, the PhantomReference test is
dubious, but I'd to propose the attached changes anyway, which I think
(hope?) will make it more robust on all VMs.

The prints are there to keep the references alive, not really nice to
use print for this, but I couldn't think of any other way that was both
simple and reliable.

Any comments?

Regards,
Jeroen