Update transformer ci/ce (#812)

* update ci/ce

* delete useless line

Author: FrostML

tests/prepare.sh

@@ -0,0 +1,5 @@
+cd ../examples/machine_translation/transformer/
+wget https://paddlenlp.bj.bcebos.com/models/transformers/transformer/tranformer-base-wmt_ende_bpe.tar.gz
+tar -zxf tranformer-base-wmt_ende_bpe.tar.gz
+mv base_trained_models/ trained_models/
+cd -