Add baseline alignment support

Summary:
Add baseline alignment support to react native.

{F65372439}

```
class Playground extends React.Component {
  render() {
    return (
      <View style={{padding: 30, flexDirection: 'row', alignItems: 'baseline'}}>
        <View style={{width: 30, height: 10, backgroundColor: 'red'}}/>
        <View style={{width: 30, height: 20, backgroundColor: 'green'}}/>
        <View style={{width: 30, height: 30, backgroundColor: 'blue'}}/>
      </View>
    );
  }
}
```

Reviewed By: javache

Differential Revision: D4385099

fbshipit-source-id: d7caa6e4c086c4a62e24ef1d5db9c805c470ef2a