Fixed double sending of onTextChange events

[vkjr]

Two TextInput bugs fixed:

1. now TextInput doesn't send "onChange" events when text was set from js side. That solves bug TextInput events repeats constantly #214
2. I found a discrepancy between multiline and singleline TextInput in Qt. When new text assigned, singleline TextInput saves cursor position, whereas multiline one - doesn't. In second case that results in cursor jumping when we quickly type in text because typed text sent to js and then assigned again from js to Qt because defaultValue changed.

PR to check in status-react: status-im/status-mobile#6176
Here is a code that reveals second problem in js:

export default class ButtonReactNative extends Component {

  constructor(props) {
    super(props);
    this.state = { newtext: "" };
  }

  render() {
    return (
      <TextInput
        style={{ backgroundColor: "yellow", width: 300, height: 100 }}
        defaultValue={this.state.newtext}
        multiline={true}
        onChangeText={text => {
          this.setState({ newtext: text })
          console.log("new text: ", text)}
        }
      />
    );
  }
}

[maxhora]

Nice catch!

[yenda]

Awesome ! What's wrong with the circle ci ?

[vkjr]

@yenda, we have one of standard react-native tests failing (because not implemented). Max recently temporary excluded it from test suite