test: cleanup, improve repl-persistent-history

- Now cleans up the history file unless told otherwise.
- Now also logs which test case failed.
- Waits for flush after repl close if necessary.

Fixes: https://github.com/nodejs/node/issues/2319
PR-URL: https://github.com/nodejs/node/pull/2356


Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed By: Evan Lucas <evanlucas@me.com>