tools: list missing whitespace/if-one-line cpplint

Writing `// NOLINT(whitespace/if-one-line)` was not possible because the
directive was not listed in the list of known lint rules.  You can now.

PR-URL: https://github.com/nodejs/node/pull/4099


Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-By: James M Snell <jasnell@gmail.com>