TEST: added new test for sct_label_utils
TEST: added new test for sct_label_utils

Former-commit-id: b3ba437eafdc23bd0409a29c8d0ffdb42db4d094 [formerly 1a8112bbb8eac6dd3a418bd19c4bfb7f7ee285ae]
Former-commit-id: ba049aa4b80fc68352fff2a69c0e95bd4b726c30
Former-commit-id: 8e4bd86ba8071fb40623aa42efca6919ee0c8c70
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox