test: refactor test-readline-interface.js

This reduces the code lines required to run the tests by abstracting
the constructor call. It also moves tests out of a for loop that
where miss placed.

PR-URL: https://github.com/nodejs/node/pull/31423


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>