Update on "Enable aoti for preprocess"

Land and update torch nightly pin after: pytorch/pytorch#137063

Test Plan:
With pytorch/pytorch#137063:
```
python -m unittest examples.models.llama3_2_vision.preprocess.test_preprocess
```

[ghstack-poisoned]

Author: lucylq

examples/models/llama3_2_vision/preprocess/export_preprocess.py

@@ -24,29 +24,22 @@ def main():
         strict=False,
     )
 
-    # Executorch
+    # AOTInductor. Note: export AOTI before ExecuTorch, as
+    # ExecuTorch will modify the ExportedProgram.
+    torch._inductor.aot_compile(
+        ep.module(),
+        model.get_example_inputs(),
+        options={"aot_inductor.output_path": "preprocess_aoti.so"},
+    )
+
+    # Executorch.
     edge_program = to_edge(
         ep, compile_config=EdgeCompileConfig(_check_ir_validity=False)
     )
     et_program = edge_program.to_executorch()
     with open("preprocess_et.pte", "wb") as file:
         et_program.write_to_file(file)
 
-    # Export.
-    # ep = torch.export.export(
-    #     model.get_eager_model(),
-    #     model.get_example_inputs(),
-    #     dynamic_shapes=model.get_dynamic_shapes(),
-    #     strict=False,
-    # )
-    #
-    # # AOTInductor
-    # torch._inductor.aot_compile(
-    #     ep.module(),
-    #     model.get_example_inputs(),
-    #     options={"aot_inductor.output_path": "preprocess_aoti.so"},
-    # )
-
 
 if __name__ == "__main__":
     main()

examples/models/llama3_2_vision/preprocess/test_preprocess.py

@@ -86,6 +86,14 @@ def initialize_models(resize_to_max_canvas: bool) -> Dict[str, Any]:
         )
         executorch_model = edge_program.to_executorch()
 
+        # Re-export, as lowering to executorch changes the graph.
+        exported_model = torch.export.export(
+            model.get_eager_model(),
+            model.get_example_inputs(),
+            dynamic_shapes=model.get_dynamic_shapes(),
+            strict=False,
+        )
+
         return {
             "config": config,
             "reference_model": reference_model,