simulate behavior is not as expected

Please suggest how to fix this scenario to simulate currentTarget object :

```
let TestComponent = React.createClass({
updateField(event){
console.log(event.target.value);
console.log(event.currentTarget.value);

this.setState({
value: event.currentTarget.value
});
},

render(){
return
}
});

```

**target.value is available in the event object as expected**

```
let component = mount();
let input = component.find("input");
input.simulate("change", {target:{value:"hello"});
```

**currentTarget.value is NOT available in the event object as expected, currentTarget is a real dom object. Looks like jsdom is overwriting it?**

```
let component = mount();
let input = component.find("input");
input.simulate("change", {currentTarget:{value:"world"});
```

Reproduce the behavior using the mount and input.simulate("change", ...) examples in the issue, comparing the target and currentTarget event fields. Start by tracing the simulate event-handling entry point and the interaction with the real DOM object or jsdom. Done means currentTarget behavior is defined and the reported scenario either works as expected or is clearly documented with a regression test.

Written by the indexing model from the issue text.