adjust tests

demos/critical_filtering.py

demos/log_normal_wiener_filter.py

demos/paper_demos/cartesian_wiener_filter.py

demos/paper_demos/wiener_filter.py

demos/probing.py

demos/wiener_filter_via_curvature.py

demos/wiener_filter_via_hamiltonian.py

nifty/data_objects/numpy_do.py

nifty/library/critical_filter/critical_power_curvature.py

nifty/sugar.py