TEST: process_segmentation: added integrity test on rotated header
TEST: process_segmentation: added integrity test on rotated header

Former-commit-id: 0e1821219f1f444a487d5fcee79ed2bbfd27c27d [formerly 075b706e002f7259d98bc0be0a84f3b0dd311989]
Former-commit-id: 17b966d3677b0db10e1cc6c1a672145c1ac81e6b
Former-commit-id: 9975d2a29419cfcae87fe59d3a9d0fa69d7fc94e
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox