tests/hwloc_object_userdata: remove a useless assert of uint>=0
tests/hwloc_object_userdata: remove a useless assert of uint>=0

ggouaillardet/hwloc,shekkbuilder/hwloc,shekkbuilder/hwloc,ggouaillardet/hwloc,shekkbuilder/hwloc,ggouaillardet/hwloc,shekkbuilder/hwloc,ggouaillardet/hwloc