I was testing latest refactor of PerfTools.
When using printOperations() often (but not always) I get 

```
Uncaught TypeError: Cannot read property 'displayName' of undefined
```

in getOperations() on the line:

```
var {displayName, ownerID} = treeSnapshot[instanceID];
```

type: 'update attribute',
          payload: { className: 'mad' },
        }, {
          instanceID: inst._debugID,
          type: 'update attribute',
          payload: { tabIndex: 42 },
        }, {
          instanceID: inst._debugID,
          type: 'remove attribute',
          payload: 'className',
        }, {
          instanceID: inst._debugID,
          type: 'update attribute',
          payload: { tabIndex: 43 },
        }]);
      });
    });
    describe('attribute that gets removed with certain values', () => {
      it('gets recorded as a removal during an update', () => {
        var node = document.createElement('div');
        ReactDOM.render(<div />, node);
        var inst = ReactDOMComponentTree.getInstanceFromNode(node.firstChild);
        ReactNativeOperationHistoryDevtool.clearHistory();
        ReactDOM.render(<div disabled={true} />, node);
        ReactDOM.render(<div disabled={false} />, node);
        assertHistoryMatches([{
          instanceID: inst._debugID,
          type: 'update attribute',
          payload: { disabled: true },
        }, {