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];
```

var ReactCurrentOwner = require('ReactCurrentOwner');
var ReactDOMComponentTree = require('ReactDOMComponentTree');
var ReactDOMContainerInfo = require('ReactDOMContainerInfo');
var ReactDOMFeatureFlags = require('ReactDOMFeatureFlags');
var ReactElement = require('ReactElement');
var ReactFeatureFlags = require('ReactFeatureFlags');
var ReactInstrumentation = require('ReactInstrumentation');
var ReactMarkupChecksum = require('ReactMarkupChecksum');
var ReactReconciler = require('ReactReconciler');
var ReactUpdateQueue = require('ReactUpdateQueue');
var ReactUpdates = require('ReactUpdates');
var emptyObject = require('emptyObject');
var instantiateReactComponent = require('instantiateReactComponent');
var invariant = require('invariant');
var setInnerHTML = require('setInnerHTML');
var shouldUpdateReactComponent = require('shouldUpdateReactComponent');
var warning = require('warning');
var ATTR_NAME = DOMProperty.ID_ATTRIBUTE_NAME;
var ROOT_ATTR_NAME = DOMProperty.ROOT_ATTRIBUTE_NAME;
var ELEMENT_NODE_TYPE = 1;
var DOC_NODE_TYPE = 9;
var DOCUMENT_FRAGMENT_NODE_TYPE = 11;
var instancesByReactRootID = {};
/**
 * Finds the index of the first character
 * that's not common between the two given strings.
 *
 * @return {number} the index of the character where the strings diverge
 */
function firstDifferenceIndex(string1, string2) {