[Test] comment os.remove cause it breaks parallel exec of test

tests/transformation/test_topk_insert.py

-import os
+# import os
 import onnx
 from finn.util.test import get_test_model_trained
 import brevitas.onnx as bo
@@ -57,4 +57,4 @@ def test_topk_insert(k):
     output_pysim_topk = output_pysim_topk.astype(np.int).flatten()
 
     assert np.array_equal(output_golden_topk, output_pysim_topk)
-    os.remove(export_onnx_path)
+    # os.remove(export_onnx_path)