Fix artery test file leak #21484

* Include actor system name in artery dir path to ease debugging leaks
* Base class name changed to make actor system autonaming work
* Add shutdown hook directly in transport start
* Wait for completion in shutdown hook (actual leak fix)

akka-remote-tests/src/multi-jvm/scala/akka/remote/RemotingMultiNodeSpec.scala

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2016 Lightbend Inc. <http://www.lightbend.com>
+ */
+package akka.remote
+
+import java.util.UUID
+
+import akka.remote.testkit.{ FlightRecordingSupport, MultiNodeConfig, MultiNodeSpec, STMultiNodeSpec }
+import akka.testkit.{ DefaultTimeout, ImplicitSender }
+import com.typesafe.config.ConfigFactory
+import org.scalatest.{ Outcome, Suite }
+
+object RemotingMultiNodeSpec {
+
+  def arteryFlightRecordingConf =
+    ConfigFactory.parseString(
+      s"""
+        akka.remote.artery.advanced.flight-recorder {
+          enabled=on
+          destination=target/flight-recorder-${UUID.randomUUID().toString}.afr
+        }
+      """)
+
+}
+
+abstract class RemotingMultiNodeSpec(config: MultiNodeConfig) extends MultiNodeSpec(config)
+  with Suite
+  with STMultiNodeSpec
+  with FlightRecordingSupport
+  with ImplicitSender
+  with DefaultTimeout { self: MultiNodeSpec ⇒
+
+  // Keep track of failure so we can print artery flight recording on failure
+  private var failed = false
+  final override protected def withFixture(test: NoArgTest): Outcome = {
+    val out = super.withFixture(test)
+    if (!out.isSucceeded)
+      failed = true
+    out
+  }
+
+  override def afterTermination(): Unit = {
+    if (failed || sys.props.get("akka.remote.artery.always-dump-flight-recorder").isDefined) {
+      printFlightRecording()
+    }
+    deleteFlightRecorderFile()
+  }
+}