Fix test_python_dispatch under debug mode (#98609)

The problem for these operators is that they were returning the input
directly as the output. This isn't support and will raise debug asserts.

Test Plan:
- Test locally. The debug build in CI doesn't actually do anything.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/98609
Approved by: https://github.com/ezyang, https://github.com/bdhirsh

test/test_python_dispatch.py

@@ -80,7 +80,7 @@ class TestPythonRegistration(TestCase):
 
         def my_sum(*args, **kwargs):
             run[0] = True
-            return args[0]
+            return args[0].clone()
 
         my_lib1 = Library("aten", "IMPL")
         my_lib1.impl('aten::sum', my_sum, "CPU")
@@ -216,7 +216,7 @@ class TestPythonRegistration(TestCase):
 
     def test_extend_library_with_dispatch_key_arg(self):
         def my_sum(*args, **kwargs):
-            return args[0]
+            return args[0].clone()
         my_lib1 = Library("aten", "IMPL", dispatch_key="CPU")
 
         # RuntimeError: Explicitly provided dispatch key (Conjugate) is
@@ -236,7 +236,7 @@ class TestPythonRegistration(TestCase):
         # Example 1
         @torch.library.impl(my_lib1, "sum", "CPU")
         def my_sum(*args, **kwargs):
-            return args[0]
+            return args[0].clone()
 
         x = torch.tensor([1, 2])
         self.assertEqual(torch.ops.foo.sum(x), x)
@@ -249,7 +249,7 @@ class TestPythonRegistration(TestCase):
             if args[0]._is_zerotensor():
                 return torch._efficientzerotensor(args[0].shape)
             else:
-                return args[0]
+                return args[0].clone()
 
         y = torch._efficientzerotensor(3)
         self.assertTrue(torch.ops.foo.sum(y)._is_zerotensor())