Concerted reaction tests should also test against reaction free energy

[samblau]

Currently, concerted reaction addition tests only check the number of concerted reactions identified / added. However, we recently missed a bug which incorrectly modified the free energy of concerted reactions without changing the number of concerted reactions that are generated. A new test should be added or a current test should be extended to also check the properties of the generated concerted reactions in addition to the number of concerted reactions.