This integration test verifies that the compat shim supports device groups.
It first creates a ‘root’ driver, which adds a node group and two child nodes that bind to its nodes.
After gathering its node, the composite formed from the node group binds to the ‘node-group’ driver. When the driver starts, it sends an ack through the fuchsia.compat.nodegroup.test.Waiter protocol.
The test waits until it receives an ack response from the ‘node-group’ driver.