fix lack file: bin/startup.sh (#3665)

* add startup.sh file

test/plugin/scenarios/postgresql-above9.4.1207-scenario/bin/startup.sh

+#!/bin/bash
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+home="$(cd "$(dirname $0)"; pwd)"
+
+java -jar ${agent_opts} ${home}/../libs/postgresql-above9.4.1207-scenario.jar &