change removeAllEquivalentVariables() to removeAllEquivalences() in test
change removeAllEquivalentVariables() to removeAllEquivalences() in test

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