sct_testing: set verbose to false by default
sct_testing: set verbose to false by default


Former-commit-id: 521c44302256a526f8b00623c2aaa129261ad79b
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox