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];
```

if (Array.isArray(node)) {
    node = node[1];
  }
  return node ? node.nextSibling : parentNode.firstChild;
}
/**
 * Inserts `childNode` as a child of `parentNode` at the `index`.
 *
 * @param {DOMElement} parentNode Parent node in which to insert.
 * @param {DOMElement} childNode Child node to insert.
 * @param {number} index Index at which to insert the child.
 * @internal
 */
var insertChildAt = createMicrosoftUnsafeLocalFunction(
  function(parentNode, childNode, referenceNode) {
    
    
    
    parentNode.insertBefore(childNode, referenceNode);
  }
);
function insertLazyTreeChildAt(parentNode, childTree, referenceNode) {