process: initial SourceMap support via NODE_V8_COVERAGE

PR-URL: https://github.com/nodejs/node/pull/28960


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>