repl: do not preview while pasting code

This makes sure no previews are triggered while pasting code. The
very last character is allowed to trigger the preview. The output
should be completely identical to the user.

PR-URL: https://github.com/nodejs/node/pull/31315


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