Revert "Fixed an issue which caused us to traverse the entire tree for OpenCSG rendering traversals, where we didn't actually use the traversal results (for all nodes requiring CGAL)"

This reverts commit 448f8b4142acb00efb7e57e575fe6d5aaabec47c.

-> We need to traverse the subtrees to be able to pick up debug and highlight modifiers
Updated tests to account for modifiers inside AbstractPolyNodes