ShutdownAllowingDeterministicScheduler suggestion to jmock

ShutdownAllowingDeterministicScheduler.java

private class ShutdownAllowingDeterministicScheduler extends DeterministicScheduler {
  override def isShutdown: Boolean = shutdownRequested

  override def isTerminated: Boolean = shutdownRequested

  override def shutdown(): Unit = shutdownRequested = true

  override def shutdownNow: util.List[Runnable] = new util.ArrayList[Runnable]

  var shutdownRequested: Boolean = false
}