node-api: force env shutdown deferring behavior

The finalizer normally never gets called while a reference is strong.
However, during environment shutdown all finalizers must get called. In
order to unify the deferring behavior with that of a regular
finalization, we must force the reference to be weak when we call its
finalizer during environment shutdown.

Fixes: https://github.com/nodejs/node/issues/37236


Co-authored-by: Chengzhong Wu <legendecas@gmail.com>
PR-URL: https://github.com/nodejs/node/pull/37303


Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>