[tests] more VectorArray tests
[la.interfaces] use amax() in sup_norm only if dim > 0
[la.listvectorarray] remove unnecessary sup_norm implementation
[la] amax() should raise exception if dim == 0
[la.listvectorarray] small fix
[la.listvectorarray] add missing assertion
[la.numpyvectorarray] add missing assertion
[tests] make older numpy versions happier
[tests] bugfix
[tests] remove some over-cautious copy() calls
[tests] remove some unneccessary tests