constructor renaming parameters

If you do this

```coffeescript
class Blah
constructor:(@thing)->
@thing()

method:->
thing = "hi"
```

Coffeescript compiles to

```javascript
var Blah;

Blah = class Blah {
constructor(thing1) {
this.thing = thing1;
this.thing();
}

method() {
var thing;
return thing = "hi";
}

};
```

Why the 1 after the thing?? I'm using an dependency injection system, and the rename is playing havoc with it. Coffeescript 1 didn't do this.

Start by compiling the minimal CoffeeScript reproduction in the issue and compare the generated constructor parameter with the CoffeeScript 1 behavior described. Trace the compiler's parameter-renaming path and confirm the dependency-injection case is preserved without the unexpected suffix; add or update a regression test if the relevant test location is identified.

Written by the indexing model from the issue text.