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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

'C',
        'Mount [A]',
        'Mount [B]',
        'Mount [C]',
        'Commit root',
        
        'Loading...',
        
        
        'Mount [Loading...]',
      ]);
      expect(ReactNoop.getChildrenAsJSX()).toEqual(
        <React.Fragment>
          <span hidden={true} prop="A" />
          <span hidden={true} prop="C" />
          <span prop="Loading..." />
        </React.Fragment>,
      );
      await advanceTimers(1000);
      expect(ReactNoop.expire(1000)).toEqual(['Promise resolved [B]', 'B']);
      expect(ReactNoop.getChildrenAsJSX()).toEqual(
        <React.Fragment>
          <span prop="A" />
          <span prop="B" />
          <span prop="C" />
        </React.Fragment>,
      );
    });
    it('suspends inside constructor', async () => {
      class AsyncTextInConstructor extends React.Component {