Extra parents when replacing an IIFE wrappedInParens

While attempting to create a transformer to remove IIFEs from a code base I started to run into issues when the IIFE used the parens-outside/`(function() {}())` style and only contained a single `ExpressionStatement`.

reproduction script: https://gist.github.com/spalger/b544122e7df96e8335ed975945931fe0
expected: all of the examples should produce the same output:
actual:

``` js

console.log('foo');
(console.log('bar'));

console.log('foo');
console.log('bar');

console.log('foo');
console.log('bar');

```

I've been debugging for a while now and can't seem to wrap my head around where this is happening. Given that [it's mentioned in this comment](http://github.com/benjamn/recast/blob/9d351c27cb981ebd65189b113c9a2aa87bbc560c/lib/patcher.js#L493) I imagine the patcher is responsible for this behavior, but that's as far as I've gotten

Start with the reproduction script in the linked gist and inspect lib/patcher.js around the referenced comment at line 493. Compare the output for the parens-outside IIFE containing one ExpressionStatement with the other examples; done means all examples produce the same output without the extra parentheses.

Written by the indexing model from the issue text.