Remove unused code from equality tests.
Remove unused code from equality tests.

cellml/libcellml,nickerso/libcellml,nickerso/libcellml,nickerso/libcellml,cellml/libcellml,hsorby/libcellml,cellml/libcellml,hsorby/libcellml,nickerso/libcellml,hsorby/libcellml,hsorby/libcellml,cellml/libcellml