See the original report in https://github.com/facebook/react/issues/10772#issuecomment-333242375.

The problem is that SVG is case sensitive, and so naïvely setting `tabIndex` and relying on insensitivity won't work with it.

The good news is it seems like `tabindex` is the only valid [SVG attribute](https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute) with this problem. We just missed it because it applies both to HTML and SVG.

I think the fix is to add it back to the whitelist. 
render() {
          return <div>{this.context.text}</div>;
        }
      }
      ClassChildWithContext.contextTypes = {text: PropTypes.string};
      const e = await render(
        <PurpleContext><ClassChildWithContext /></PurpleContext>,
      );
      expect(e.textContent).toBe('purple');
    });
    itRenders('stateless child with context', async render => {
      function StatelessChildWithContext(props, context) {
        return <div>{context.text}</div>;
      }
      StatelessChildWithContext.contextTypes = {text: PropTypes.string};
      const e = await render(
        <PurpleContext><StatelessChildWithContext /></PurpleContext>,
      );
      expect(e.textContent).toBe('purple');
    });
    itRenders('class child without context', async render => {
      class ClassChildWithoutContext extends React.Component {