AUI-1320 Revert "AUI-950 TreeView Tasks IO Nodes are unable to expand and reveal their children"

This reverts commit 71b94624c8335aa2deae1962067fe52d47dd011b.

Conflicts:
	src/aui-tree/js/aui-tree-node.js

AUI-950 was fixed by AUI-1014. Since AUI-950 causes AUI-1320, and was never affecting master nor master-deprecated, we should revert this commit everywhere.