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.

I verified that test/async-hooks/test-callback-error.js properly tests this.

First time contributing to the C++ side of Node, please send all the advice 😆

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

lib, src, async_hooks