[Test] shape inf + fold consts to get rid of Cast in ToTensor

tests/end2end/test_end2end_bnn_pynq.py

@@ -347,6 +347,8 @@ class TestEnd2End:
         assert os.path.isfile(chkpt_preproc_name)
         # join preprocessing and core model
         pre_model = ModelWrapper(chkpt_preproc_name)
+        pre_model = pre_model.transform(InferShapes())
+        pre_model = pre_model.transform(FoldConstants())
         model = model.transform(MergeONNXModels(pre_model))
         # add input quantization annotation: UINT8 for all BNN-PYNQ models
         global_inp_name = model.graph.input[0].name

tests/end2end/test_end2end_mobilenet_v1.py

@@ -101,6 +101,7 @@ def test_end2end_mobilenet_export():
     # set input finn datatype to UINT8
     preproc_model.set_tensor_datatype(preproc_model.graph.input[0].name, DataType.UINT8)
     preproc_model = preproc_model.transform(InferShapes())
+    preproc_model = preproc_model.transform(FoldConstants())
     preproc_model = preproc_model.transform(GiveUniqueNodeNames())
     preproc_model = preproc_model.transform(GiveUniqueParameterTensors())
     preproc_model = preproc_model.transform(GiveReadableTensorNames())