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**Do you want to request a *feature* or report a *bug*?** Bug, I guess

**What is the current behavior?** 


```
  console.error node_modules/fbjs/lib/warning.js:33
    Warning: Detected multiple renderers concurrently rendering the same context provider. This is currently unsupported.
```

Steps to reproduce the behavior:
1. `git clone https://github.com/stereobooster/react-context-issue`
2. `cd react-context-issue`
3. `yarn`
4. `yarn test`

**What is the expected behavior?** no warning

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?** React 16.4. Browser not affected, because error is in node.js

Open this because of https://github.com/facebook/react/pull/13127#issuecomment-402527012

Issue happens because of Enzyme (https://github.com/airbnb/enzyme/issues/1693), code is unreleased, so I copy-pasted it from master. 

I'm looking for advice or some clue on how to fix this, so I would be able to create PR in Enzyme repo (or in React repo if this is the case). Thank you.


Surface = ReactART.Surface;
    TestComponent = class extends React.Component {
      group = React.createRef();
      render() {
        const a = (
          <Shape
            d="M0,0l50,0l0,50l-50,0z"
            fill={new ReactART.LinearGradient(['black', 'white'])}
            key="a"
            width={50}
            height={50}
            x={50}
            y={50}
            opacity={0.1}
          />
        );
        const b = (
          <Shape
            fill="#3C5A99"
            key="b"
            scale={0.5}
            x={50}
            y={50}
            title="This is an F"
            cursor="pointer">
            M64.564,38.583H54l0.008-5.834c0-3.035,0.293-4.666,4.657-4.666
            h5.833V16.429h-9.33c-11.213,0-15.159,5.654-15.159,15.16v6.994
            h-6.99v11.652h6.99v33.815H54V50.235h9.331L64.564,38.583z
          </Shape>
        );