Validator: removed an unneeded test.
Validator: removed an unneeded test.

We are iterating through (existing) equivalent variables, so we should never have a null equivalent variable...?

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