Based on https://github.com/prettier/prettier/pull/2676
* Thread `path` and `options` through helpers so we don't need to add `needsParens` onto the AST node anymore (mutation)
* Pull test call detection logic out into helper method so it can be re-used for arrow function parens
* Add arrow function parens option implementation (avoid/always)
* Don't break arrow function parens around (done) in test call