update model tests with shorttag serialisation of models
update model tests with shorttag serialisation of models

hsorby/libcellml,hsorby/libcellml,MichaelClerx/libcellml,hsorby/libcellml,MichaelClerx/libcellml,MichaelClerx/libcellml,cellml/libcellml,libcellml/buildbot-testing,nickerso/libcellml,nickerso/libcellml,cellml/libcellml,nickerso/libcellml,nickerso/libcellml,cellml/libcellml,cellml/libcellml,libcellml/buildbot-testing,hsorby/libcellml