This is a bug in `React.createElement` code:

`React.createElement` does not warn if `props.__proto__` is null ( from `Object.create(null)` ) since it [believes that to be a plain object](https://github.com/facebook/react/blob/master/src/isomorphic/classic/element/ReactElement.js#L135) originating from #6134. But since it directly accesses `hasOwnProperty` it fails if such object is passed as props.

Reproduce:

``` js
const props = Object.create(null);
React.createElement(() => null, props);
```

**What is the expected behavior?**
It shouldn't use `hasOwnProperty` directly on props if such object is expected.

React: 15.1.0
Browsers: All
OS: All

This affects all versions of React but since after 15.1.0 the acceptable shape of props is explicitly defined then it should be explicitly supported as well.

ReactDOM = require('ReactDOM');
    ReactTestUtils = require('ReactTestUtils');
    
    
    ComponentClass = React.createClass({
      render: function() {
        return React.createElement('div');
      },
    });
  });
  afterEach(function() {
    global.Symbol = originalSymbol;
  });
  it('uses the fallback value when in an environment without Symbol', function() {
    expect(<div />.$$typeof).toBe(0xeac7);
  });
  it('returns a complete element according to spec', function() {
    var element = React.createFactory(ComponentClass)();
    expect(element.type).toBe(ComponentClass);
    expect(element.key).toBe(null);
    expect(element.ref).toBe(null);
    var expectation = {};
    Object.freeze(expectation);
    expect(element.props).toEqual(expectation);
  });
  it('should warn when `key` is being accessed', function() {
    spyOn(console, 'error');
    var container = document.createElement('div');
    var Child = React.createClass({
      render: function() {