<!--
  Note: if the issue is about documentation or the website, please file it at:
  https://github.com/reactjs/reactjs.org/issues/new
-->

**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

'Suspend! [A]',
        'Loading...',
      ]);
      jest.advanceTimersByTime(1000);
      expect(ReactTestRenderer).toHaveYielded(['Promise resolved [A]', 'A']);
      expect(root).toMatchRenderedOutput('Stateful: 1A');
      root.update(<App text="B" />);
      expect(ReactTestRenderer).toHaveYielded([
        'Stateful: 1',
        'Suspend! [B]',
        'Loading...',
      ]);
      expect(root).toMatchRenderedOutput('Loading...');
      instance.setState({step: 2});
      expect(ReactTestRenderer).toHaveYielded([
        'Stateful: 2',
        'Suspend! [B]',
        'Loading...',
      ]);
      expect(root).toMatchRenderedOutput('Loading...');
      jest.advanceTimersByTime(1000);
      expect(ReactTestRenderer).toHaveYielded([
        'Promise resolved [B]',
        'B',
        'B',
      ]);
      expect(root).toMatchRenderedOutput('Stateful: 2B');
    });
    it('suspends in a class that has componentWillUnmount and is then deleted', () => {
      class AsyncTextWithUnmount extends React.Component {