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**Do you want to request a *feature* or report a *bug*?**
bug, I believe, unless I misunderstand how it works
**What is the current behavior?**
Given a `Suspense` inside `Suspense` case like
```
<Suspense fallback="Fallback 1">
  <LazyText1 text="First text" />
  <Suspense fallback="Fallback 2">
    <LazyText2 text="Second text!" />
  </Suspense>
</Suspense>
```

Promises in `LazyTexts` start resolving at the same time, but if `LazyText2` is resolved first it never renders, `Fallback 2` stays.

Result:
```
First text

Fallback 2
```

Please see https://codesandbox.io/s/234o4zry7n

**What is the expected behavior?**

Every `LazyText` displayed in the end
```
First text

Second text!
```

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
react, react-dom 16.6.0

ReactNoop.yield(`Update [${this.props.text}]`);
      }
      componentWillUnmount() {
        ReactNoop.yield(`Unmount [${this.props.text}]`);
      }
      render() {
        const text = this.props.text;
        const ms = this.props.ms;
        try {
          TextResource.read([text, ms]);
          ReactNoop.yield(text);
          return <span prop={text} />;
        } catch (promise) {
          if (typeof promise.then === 'function') {
            ReactNoop.yield(`Suspend! [${text}]`);
          } else {
            ReactNoop.yield(`Error! [${text}]`);
          }
          throw promise;
        }
      }
    }
    function App() {
      return (
        <Suspense
          maxDuration={1000}
          fallback={<TextWithLifecycle text="Loading..." />}>
          <TextWithLifecycle text="A" />
          <AsyncTextWithLifecycle ms={100} text="B" />