test: mark test optimization test as no longer broken

Author: AayushSabharwal

test/optimizationsystem.jl

@@ -73,7 +73,7 @@ end
     prob = OptimizationProblem(sys, [x => 0.0, y => 0.0, a => 1.0, b => 1.0],
         grad = false, hess = false, cons_j = false, cons_h = false)
     sol = solve(prob, AmplNLWriter.Optimizer(Ipopt_jll.amplexe))
-    @test_skip sol.objective < 1.0
+    @test sol.objective < 1.0
 end
 
 @testset "equality constraint" begin