quic: always copy stateless reset token

Take ownership of the token value, since the memory for it is allocated
anyway and the buffer size is just 16, i.e. copyable very cheaply.

This makes valgrind stop complaining about a use-after-free error
when running `sequential/test-quic-preferred-address-ipv6`.

PR-URL: https://github.com/nodejs/node/pull/33917


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>