lib: use getOptionValue instead of process underscore aliases

This patch reduce usage of `process._breakFirstLine` and
`process._eval` in the internals and use
`getOptionValue('--inspect-brk')` and `getOptionValue('--eval')`
instead wherever possible.

PR-URL: https://github.com/nodejs/node/pull/27278


Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Anna Henningsen <anna@addaleax.net>