Created by: luotao1

related #9629 (closed). When use insert_op method for stage 1, there is error in sync_with_cpp. The reason is that sync_with_cpp only consider remove_op, append_op, prepend_op, remove_var now, but don't consider insert_op.

Thus, this PR consider insert_op in sync_with_cpp, and add a unit test to check the sync_with_cpp after calling append_op, prepend_op and insert_op.