test: improve readline test coverage for tty

Adds the following tests for tty readline:
- go to beginning and end of line
- wordLeft
- wordRight
- deleteWordLeft
- deleteWordRight

PR-URL: https://github.com/nodejs/node/pull/12064


Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>