Revert "fix(treelist): Restored test for node.isHidden"
Revert "fix(treelist): Restored test for node.isHidden"

This reverts commit 6e2f4c4cc88e9ac3d056b636baf1b0b2800db5f2.

fabric8-ui/fabric8-ui,fabric8io/fabric8-ui,fabric8-ui/fabric8-ui,fabric8-ui/fabric8-ui,fabric8io/fabric8-ui,fabric8io/fabric8-ui,fabric8io/fabric8-ui,fabric8-ui/fabric8-ui,fabric8-ui/fabric8-ui,fabric8io/fabric8-ui