Update on "Implement aten::index | feat(torchlib) (#862)"

Gather op:
- https://github.com/openxla/xla/blob/main/docs/operation_semantics.md?rgh-link-date=2023-07-13T01%3A09%3A16Z#gather
- https://www.pathpartnertech.com/gather-scatter-operation-in-deep-learning-framework/

---------

Co-authored-by: BowenBao <bowbaomicrosoft.com>

[ghstack-poisoned]

Author: justinchuby

onnxscript/tests/function_libs/torch_lib/ops_test_common.py

@@ -513,14 +513,12 @@ def _capture_graph_and_evaluate_torch_script_evaluator(function: Callable, args,
 
         onnx_model = onnxscript_graph.to_model_proto(TEST_OPSET_VERSION)
         # Make sure the model is valid
-        # try:
-        #     onnx.checker.check_model(onnx_model, full_check=True)
-        # except (onnx.checker.ValidationError, onnx.shape_inference.InferenceError) as e:
-        #     raise AssertionError(
-        #         f"ONNX model is invalid. Model:\n{onnxscript.proto2text(onnx_model)}"
-        #     ) from e
-
-        print(onnxscript.proto2text(onnx_model))
+        try:
+            onnx.checker.check_model(onnx_model, full_check=True)
+        except (onnx.checker.ValidationError, onnx.shape_inference.InferenceError) as e:
+            raise AssertionError(
+                f"ONNX model is invalid. Model:\n{onnxscript.proto2text(onnx_model)}"
+            ) from e
 
         try:
             if os.environ.get("CATCH_ORT_SEGFAULT") == "1":