Fix path created for output of 4D images in test
Fix path created for output of 4D images in test

There was missing a directory separator.

kaspermarstal/SimpleElastix,richardbeare/SimpleITK,SimpleITK/SimpleITK,SimpleITK/SimpleITK,richardbeare/SimpleITK,blowekamp/SimpleITK,richardbeare/SimpleITK,kaspermarstal/SimpleElastix,InsightSoftwareConsortium/SimpleITK,InsightSoftwareConsortium/SimpleITK,blowekamp/SimpleITK,kaspermarstal/SimpleElastix,SimpleITK/SimpleITK,richardbeare/SimpleITK,blowekamp/SimpleITK,InsightSoftwareConsortium/SimpleITK,kaspermarstal/SimpleElastix,blowekamp/SimpleITK,blowekamp/SimpleITK,blowekamp/SimpleITK,SimpleITK/SimpleITK,blowekamp/SimpleITK,InsightSoftwareConsortium/SimpleITK,kaspermarstal/SimpleElastix,InsightSoftwareConsortium/SimpleITK,richardbeare/SimpleITK,blowekamp/SimpleITK,InsightSoftwareConsortium/SimpleITK,kaspermarstal/SimpleElastix,richardbeare/SimpleITK,SimpleITK/SimpleITK,richardbeare/SimpleITK,SimpleITK/SimpleITK,InsightSoftwareConsortium/SimpleITK,SimpleITK/SimpleITK,richardbeare/SimpleITK,kaspermarstal/SimpleElastix,InsightSoftwareConsortium/SimpleITK,SimpleITK/SimpleITK