Replace legacy tensor.Tensor with torch.tensor/torch.empty (#12027)

* Replace legacy torch.Tensor constructor with torch.{tensor, empty}

* Remove torch.Tensor in examples

tests/test_activations.py

@@ -27,7 +27,7 @@ if is_torch_available():
 @require_torch
 class TestActivations(unittest.TestCase):
     def test_gelu_versions(self):
-        x = torch.Tensor([-100, -1, -0.1, 0, 0.1, 1.0, 100])
+        x = torch.tensor([-100, -1, -0.1, 0, 0.1, 1.0, 100])
         torch_builtin = get_activation("gelu")
         self.assertTrue(torch.eq(_gelu_python(x), torch_builtin(x)).all().item())
         self.assertFalse(torch.eq(_gelu_python(x), gelu_new(x)).all().item())