Remove Gumbel test - the new test suite should cover that

pymc3/tests/test_distributions_random.py

@@ -1137,13 +1137,6 @@ def test_dirichlet_multinomial_dist_ShapeError(self, n, a, shape, expectation):
         with expectation:
             m.random()
 
-    @pytest.mark.xfail(reason="This distribution has not been refactored for v4")
-    def test_gumbel(self):
-        def ref_rand(size, mu, beta):
-            return st.gumbel_r.rvs(loc=mu, scale=beta, size=size)
-
-        pymc3_random(pm.Gumbel, {"mu": R, "beta": Rplus}, ref_rand=ref_rand)
-
     @pytest.mark.xfail(reason="This distribution has not been refactored for v4")
     def test_logistic(self):
         def ref_rand(size, mu, s):