testing: sct_apply_transfo: add basic integrity checking
testing: sct_apply_transfo: add basic integrity checking

Former-commit-id: e0cbd0baa146aa42ba3b5ab981bd05e8f17ca7d3
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox