[wpilib] Remove IterativeRobot base class

TimedRobot supersedes it (see commit 81498e6 for reasoning).

wpilibc/src/main/native/include/frc/IterativeRobot.h

@@ -1,50 +0,0 @@
-// Copyright (c) FIRST and other WPILib contributors.
-// Open Source Software; you can modify and/or share it under the terms of
-// the WPILib BSD license file in the root directory of this project.
-
-#pragma once
-
-#include <atomic>
-
-#include "frc/IterativeRobotBase.h"
-
-namespace frc {
-
-/**
- * IterativeRobot implements the IterativeRobotBase robot program framework.
- *
- * The IterativeRobot class is intended to be subclassed by a user creating a
- * robot program.
- *
- * Periodic() functions from the base class are called each time a new packet is
- * received from the driver station.
- *
- * @deprecated Use TimedRobot instead. It's a drop-in replacement that provides
- * more regular execution periods.
- */
-class IterativeRobot : public IterativeRobotBase {
- public:
-  WPI_DEPRECATED(
-      "Use TimedRobot instead. It's a drop-in replacement that provides more "
-      "regular execution periods.")
-  IterativeRobot();
-  ~IterativeRobot() override = default;
-
-  /**
-   * Provide an alternate "main loop" via StartCompetition().
-   *
-   * This specific StartCompetition() implements "main loop" behavior synced
-   * with the DS packets.
-   */
-  void StartCompetition() override;
-
-  /**
-   * Ends the main loop in StartCompetition().
-   */
-  void EndCompetition() override;
-
- private:
-  std::atomic<bool> m_exit{false};
-};
-
-}  // namespace frc