remove disconnects from tests

test/distributed_test.py

@@ -57,7 +57,6 @@ def test_gather(backend):
                  [1., 1., 1., 1., 3., 3., 3., 3.]]
             ))
 
-        comm.Disconnect()
     else:
         rs.num_proc = (2, 2)
 
@@ -131,7 +130,6 @@ def test_scatter(backend):
             comm.Recv(res, proc)
             assert np.array_equal(res, global_arr[idx])
 
-        comm.Disconnect()
     else:
         rs.num_proc = (2, 2)
 
@@ -208,7 +206,6 @@ def test_acc(backend):
 
         np.testing.assert_allclose(sim.state.psi / scale, other_psi / scale, rtol=0, atol=1e-5)
 
-        comm.Disconnect()
     else:
         rs.num_proc = (2, 2)