lib, src: use process.config instead of regex

Is safer to use a `process.binding(config)` defined boolean, than to
regex on `process.execArgv`. Also, this better falls in line with the
conventions of checking flags passed to the executable.

PR-URL: https://github.com/nodejs/node/pull/17814


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