This commit adds a check to see if an environment variable that is
found in the .env file is already set in the environment. If it is,
then the value from the .env file is not used.
PR-URL: https://github.com/nodejs/node/pull/49424
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>