STYLE: Use keyword style for HeaderTest target_link_libraries
STYLE: Use keyword style for HeaderTest target_link_libraries

Use the more modern explicit keyword-style.

BRAINSia/ITK,thewtex/ITK,richardbeare/ITK,BRAINSia/ITK,hjmjohnson/ITK,hjmjohnson/ITK,InsightSoftwareConsortium/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK,thewtex/ITK,thewtex/ITK,InsightSoftwareConsortium/ITK,thewtex/ITK,Kitware/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK,richardbeare/ITK,Kitware/ITK,InsightSoftwareConsortium/ITK,BRAINSia/ITK,hjmjohnson/ITK,thewtex/ITK,Kitware/ITK,Kitware/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK,BRAINSia/ITK,thewtex/ITK,BRAINSia/ITK,BRAINSia/ITK,hjmjohnson/ITK,hjmjohnson/ITK,Kitware/ITK,hjmjohnson/ITK,Kitware/ITK,InsightSoftwareConsortium/ITK,thewtex/ITK,BRAINSia/ITK,hjmjohnson/ITK,richardbeare/ITK,richardbeare/ITK,Kitware/ITK