worker: provide process.execArgv

Provide `process.execArgv`. If an `execArgv` option is passed to the
`Worker` constructor, that option is used as its value; if not,
the parent’s `process.execArgv` is inherited (since that also goes
for the actual options in that case).

PR-URL: https://github.com/nodejs/node/pull/26267


Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>