benchmark,test,lib: remove extra spaces

In preparation for stricter linting, remove extra spaces.

PR-URL: https://github.com/nodejs/node/pull/6645


Reviewed-By: Michaël Zasso <mic.besace@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: Roman Reiss <me@silverwind.io>