[SPARK-13621][CORE] TestExecutor.scala needs to be moved to test package

Moved TestExecutor.scala from src to test package and removed the unused file TestClient.scala.

Author: Devaraj K <devaraj@apache.org>

Closes #11474 from devaraj-kavali/SPARK-13621.

core/src/main/scala/org/apache/spark/deploy/client/TestClient.scala

-/*
- * 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.
- */
-
-package org.apache.spark.deploy.client
-
-import org.apache.spark.{Logging, SecurityManager, SparkConf}
-import org.apache.spark.deploy.{ApplicationDescription, Command}
-import org.apache.spark.rpc.RpcEnv
-import org.apache.spark.util.Utils
-
-private[spark] object TestClient {
-
-  private class TestListener extends AppClientListener with Logging {
-    def connected(id: String) {
-      logInfo("Connected to master, got app ID " + id)
-    }
-
-    def disconnected() {
-      logInfo("Disconnected from master")
-      System.exit(0)
-    }
-
-    def dead(reason: String) {
-      logInfo("Application died with error: " + reason)
-      System.exit(0)
-    }
-
-    def executorAdded(id: String, workerId: String, hostPort: String, cores: Int, memory: Int) {}
-
-    def executorRemoved(id: String, message: String, exitStatus: Option[Int]) {}
-  }
-
-  def main(args: Array[String]) {
-    val url = args(0)
-    val conf = new SparkConf
-    val rpcEnv = RpcEnv.create("spark", Utils.localHostName(), 0, conf, new SecurityManager(conf))
-    val executorClassname = TestExecutor.getClass.getCanonicalName.stripSuffix("$")
-    val desc = new ApplicationDescription("TestClient", Some(1), 512,
-      Command(executorClassname, Seq(), Map(), Seq(), Seq(), Seq()), "ignored")
-    val listener = new TestListener
-    val client = new AppClient(rpcEnv, Array(url), desc, listener, new SparkConf)
-    client.start()
-    rpcEnv.awaitTermination()
-  }
-}