Skip model load when lowering (#4103)

Summary:
Model load is not required, loading incurs a performance hit.

Pull Request resolved: #4103

Reviewed By: kirklandsign

Differential Revision: D59286563

Pulled By: cccclai

fbshipit-source-id: 08e73afc217f8e80a1d9c5adaa562667c17b2b92

Author: cymbalrush

backends/apple/coreml/compiler/coreml_preprocess.py

@@ -386,7 +386,7 @@ def preprocess(
             source="pytorch",
             convert_to="mlprogram",
             pass_pipeline=ct.PassPipeline.DEFAULT,
-            skip_model_load=False,
+            skip_model_load=True,
             compute_precision=model_compute_precision,
             minimum_deployment_target=minimum_deployment_target,
             compute_units=compute_units,