src: call `Environment::Exit()` for fatal exceptions

Call `Environment::Exit()` rather than the process-wide
`exit()` function, since JS exceptions generally only affect
the current JS engine instance.

PR-URL: https://github.com/nodejs/node/pull/25472


Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Minwoo Jung <minwoo@nodesource.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>