[dynamo] Fix for #127696 (#128530)

[dynamo] Fix for #127696 (#128358)

Test Plan:
`buck2 test @//mode/dev-nosan //executorch/exir/backend/...`
https://www.internalfb.com/intern/testinfra/testrun/12666373989243932

Differential Revision: D58384518

Pull Request resolved: #128358
Approved by: https://github.com/ydwu4

(cherry picked from commit 4345d98)

Co-authored-by: Angela Yi <angelayi@meta.com>

torch/_dynamo/variables/higher_order_ops.py

@@ -12,7 +12,7 @@
 import torch.fx
 import torch.nn
 import torch.onnx.operators
-from torch._dynamo.utils import deepcopy_to_fake_tensor, get_fake_value, get_real_value
+from torch._dynamo.utils import get_fake_value
 from torch._dynamo.variables import ConstantVariable
 from torch._dynamo.variables.base import VariableTracker
 from torch._dynamo.variables.builtin import BuiltinVariable
@@ -1149,17 +1149,15 @@ def call_function(
 
         p_args = tuple(arg.as_proxy() for arg in args[1:])
         real_sub_args = pytree.tree_map_only(
-            torch.fx.Proxy, lambda a: get_real_value(a.node, tx.output), p_args
+            torch.fx.Proxy, lambda a: get_fake_value(a.node, tx), p_args
         )
 
-        example_res = lowered_module.original_module.module()(*real_sub_args)
+        example_value = lowered_module.original_module.module()(*real_sub_args)
 
         # NOTE [Guaranteeing the 1-1 correspondence of FakeTensors and real tensors]:
         # executorch modules promise not to alias inputs and outputs.
         # Thus, output FakeTensors will correctly not alias input FakeTensors.
-        _assert_tensors_nonaliasing(real_sub_args, example_res)
-
-        example_value = deepcopy_to_fake_tensor(example_res, tx.fake_mode)
+        _assert_tensors_nonaliasing(real_sub_args, example_value)
 
         p_args = (lowered_node,) + p_args