tools: enable additional lint rules

Enable additional likely-uncontroversial lint rules:

* `comma-dangle` set to prohibit dangling commas on objects and arrays
that are defined on a single line. Multi-line definitions can use or
omit a trailing comma.

* `no-unused-labels` Prohibits defining a label that is not used.

* `no-path-concat` Prohibits string-concatenation using i`__dirname` and
`__filename`. Use `path.join()`, `path.resolve()`, or template strings
instead.

* `no-new-symbol` disallow use of `new` operator with `Symbol` object.
Violating this rule would result in a `TypeError` at runtime.`

PR-URL: https://github.com/nodejs/node/pull/5357


Reviewed-By: Rod Vagg <rod@vagg.org>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michaël Zasso <mic.besace@gmail.com>