tools: enable no-extra-parens in ESLint

Enable `no-extra-parens`. This rule restricts the use of parentheses to
only where they are necessary. It is set to be restricted to report only
function expressions.

PR-URL: https://github.com/nodejs/node/pull/5512


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: James M Snell <jasnell@gmail.com>