Adapt for new syntax of model_diagnostics

tests/second_order/ds1.mod

@@ -64,6 +64,6 @@ end;
 
 resid(1);
 steady;
-model_diagnostics(M_,options_,oo_);
+model_diagnostics;
 check;
 stoch_simul(order=2,irf=0);

tests/second_order/ds2.mod

@@ -64,7 +64,7 @@ end;
 
 resid(1);
 steady;
-model_diagnostics(M_,options_,oo_);
+model_diagnostics;
 check;
 stoch_simul(order=2,irf=0);