Add: test code for CoreMLExecutionProvider on a trial basis

Currently ONNXRuntime's CoreML support is not very good, and on my environment, I get errors like “coreml_execution_provider.cc:192 operator() Input (/sdp/flows.3/GatherND_2_output_0) has a dynamic shape ({-1,-1}) but the runtime shape ({0,10}) has zero elements. This is not supported by the CoreML EP.” and inference fails.
I hope this will be fixed in a future version of ONNXRuntime, and leave the test code as it is.

tests/test_main.py

@@ -125,3 +125,12 @@ def test_synthesize_onnx_directml():
             ("DmlExecutionProvider", {"device_id": 0}),
         ],
     )
+
+
+def test_synthesize_onnx_coreml():
+    synthesize(
+        inference_type="onnx",
+        onnx_providers=[
+            ("CoreMLExecutionProvider", {}),
+        ],
+    )