Update WWSafe.pm.

The updated `WWSafe.pm` is based on version 2.47 of the upstream
`Safe.pm` module. It is essentially the upstream module except that some
reentrancy issues with `reval` and `rdo`, and an issue with sharing an
entire package to the safe compartment are fixed.

These are basically the same changes as to the WWSafe.pm module for PG.

Author: drgrice1