src: remove finalized_ member from Hash class

This commit removes the finalized_ member from the Hash class as it does
not seem to be used in any valuable way. Commit c75f87cc ("crypto:
refactor the crypto module") removed the check where it was previously
used.

PR-URL: https://github.com/nodejs/node/pull/24822


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>