Add option to export phi-3-mini model via buck2

Pull Request resolved: #4189

as title
ghstack-source-id: 233306024
@exported-using-ghexport

Differential Revision: [D59500806](https://our.internmc.facebook.com/intern/diff/D59500806/)

Author: helunwencser

examples/models/phi-3-mini/export_model.py renamed to examples/models/phi-3-mini/export_phi-3-mini.py

@@ -19,9 +19,10 @@
     get_symmetric_quantization_config,
     XNNPACKQuantizer,
 )
-from torch.export import export
 
-from transformers import Phi3ForCausalLM
+from transformers import (  # @manual=fbsource//third-party/pypi/transformers:transformers
+    Phi3ForCausalLM,
+)
 
 
 def main() -> None:
@@ -48,8 +49,14 @@ def main() -> None:
         model(*example_inputs)
         model = convert_pt2e(model, fold_quantize=False)
         DuplicateDynamicQuantChainPass()(model)
-        model = export(
-            model, example_inputs, dynamic_shapes=dynamic_shape, strict=False
+        # TODO(lunwenh): update it to use export once
+        # https://github.com/pytorch/pytorch/issues/128394 is resolved.
+        model = torch.export._trace._export(
+            model,
+            example_inputs,
+            dynamic_shapes=dynamic_shape,
+            strict=False,
+            pre_dispatch=False,
         )
 
     edge_config = get_xnnpack_edge_compile_config()