Test handler only supports calling properties that are a function

**Bug**

It doesn't look the new test renderer supports the same type of functional handler to call a function in an property that is an object, it only supports calling properties that are function at the moment.

When

Package Version: Dojo 7

**Code**

https://gist.github.com/webdevisme/c05b9aaa5b642a37b7b2ebfa3454871c

**Expected behavior:**

Final test case to pass after triggering global mouse events in test renderer

**Actual behavior:**

Mouse events are not triggered, test fails