repl: handle buffered string logic on finish

Looks like `clearBufferedCommand` will be called on almost all flows.
Hence history was broken.

PR-URL: https://github.com/nodejs/node/pull/24389
Fixes: https://github.com/nodejs/node/issues/24385


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>