Check feasibility of unifying contour tree pointer jumping with that of UnionFind.h
@kmorel pointed out that @ollielo has implemented pointer jumping in
that went through many iterations to work correctly (see !2723 (merged) for more details). @ghweber, @oruebel, Petar Hristov and Hamish Carr should follow up with @ollielo to see if the contour tree implementation has any bugs/issues and whether we can unify it with the one used in vtk-m union find.