chore: Remove SecurityManager usage. (#2106)

bench-jmh/src/main/scala/org/apache/pekko/util/StackBench.scala

@@ -1,41 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * license agreements; and to You under the Apache License, version 2.0:
- *
- *   https://www.apache.org/licenses/LICENSE-2.0
- *
- * This file is part of the Apache Pekko project, which was derived from Akka.
- */
-
-/*
- * Copyright (C) 2009-2022 Lightbend Inc. <https://www.lightbend.com>
- */
-
-package org.apache.pekko.util
-
-import java.util.concurrent.TimeUnit
-import scala.annotation.nowarn
-
-import org.openjdk.jmh.annotations.{ Benchmark, Measurement, Scope, State }
-
-@State(Scope.Benchmark)
-@Measurement(timeUnit = TimeUnit.MICROSECONDS)
-class StackBench {
-
-  @nowarn("msg=deprecated")
-  class CustomSecurtyManager extends SecurityManager {
-    def getTrace: Array[Class[_]] =
-      getClassContext
-  }
-
-  @Benchmark
-  def currentThread(): Array[StackTraceElement] = {
-    Thread.currentThread().getStackTrace
-  }
-
-  @Benchmark
-  def securityManager(): Array[Class[_]] = {
-    (new CustomSecurtyManager).getTrace
-  }
-
-}