Fix compilation on macOS by adding virtual destructors (#3878)

src/ray/raylet/scheduling_queue.h

@@ -49,6 +49,9 @@ enum class TaskState {
 
 class TaskQueue {
  public:
+  /// TaskQueue destructor.
+  virtual ~TaskQueue() {}
+
   /// \brief Append a task to queue.
   ///
   /// \param task_id The task ID for the task to append.
@@ -103,6 +106,9 @@ class ReadyQueue : public TaskQueue {
 
   ReadyQueue(const ReadyQueue &other) = delete;
 
+  /// ReadyQueue destructor.
+  virtual ~ReadyQueue() {}
+
   /// \brief Append a task to queue.
   ///
   /// \param task_id The task ID for the task to append.