Testing that the ContentFlows events are correctly dispatched when nodes are attached to/detached from a flow.

PASS: ContentFlow was added.
PASS: ContentFlow.contentNodes has a length of 2.
PASS: ContentFlow.contentNodes[0].id is "#contentStatic".
PASS: ContentFlow.contentNodes[1].id is "#contentRemoved".
PASS: "#contentAddedAtTheTop" was added before "#contentStatic".
PASS: "#contentAddedAtTheTop" is first in the contentNodes list.
PASS: "#contentAddedAtTheBottom" was added last.
PASS: "#contentAddedAtTheBottom" is last in the contentNodes list.
PASS: "#contentRemoved" was removed.
PASS: "#contentRemoved" cannot be found in the contentNodes list.