Is this a bug report?

Yes

Have you read the Contributing Guidelines?

(Write your answer here.)

Environment

Environment:
OS: macOS Sierra 10.12.6
Node: 8.9.1
Yarn: 1.3.2
npm: 5.6.0
Watchman: 4.9.0
Xcode: Xcode 9.2 Build version 9C40b
Android Studio: 3.0 AI-171.4443003

Packages: (wanted => installed)
react: 16.0.0 => 16.0.0
react-native: 0.52.0 => 0.52.0

Steps to Reproduce

(Write your steps here:)

1. Make a fetch request to a malformed url like https://http:.malformedurl.com
2. The error is not propagated to the promise resolvers

Expected Behavior

The error should be thrown in the Javascript so that it can be caught in the catch block

Actual Behavior

(Write what happened. Add screenshots!)

Reproducible Demo

test = async () => {
    try {
      await fetch('https://http:.malformedurl.com/.jsapi/info')
      console.log('Fetch successful')
    }
    catch(error) {
      console.error(error); // never goes here
    }
    
  }
  componentDidMount() {
    this.test();
  }