Test multiple CSS.takeComputedStyleUpdates commands at the same time.
Sending a request before the previous one is resolved should fail with an error message:
{
    code : -32000
    message : A previous request has not been resolved yet.
}
[
]
Updated nodes should contain the first item: true
Updated nodes should contain the second item: true
Updated nodes should not contain the third item: true
Updated nodes should not contain the fourth item: true