[sim] Move Sim classes from HAL to wpilibc/j (#2549)

Also move some things in HAL for consistency.

WAS:
C++:
- C APIs: #include "mockdata/AccelerometerData.h"
- User side class: #include "simulation/AccelerometerSim.h"
Java:
- JNI APIs: hal.sim.mockdata.AccelerometerData (and a few classes in hal.sim)
- User side classes: hal.sim.AccelerometerSim

IS:
C++:
- C APIs: #include "hal/simulation/AccelerometerData.h"
- C++ class: #include "frc/simulation/AccelerometerSim.h"
Java:
- JNI APIs: hal.simulation.AccelerometerData
- User side class: wpilibj.simulation.AccelerometerSim

wpilibNewCommands/src/test/native/cpp/frc2/command/CommandTestBase.h

@@ -1,5 +1,5 @@
 /*----------------------------------------------------------------------------*/
-/* Copyright (c) 2019 FIRST. All Rights Reserved.                             */
+/* Copyright (c) 2019-2020 FIRST. All Rights Reserved.                        */
 /* Open Source Software - may be modified and shared by FRC teams. The code   */
 /* must be accompanied by the FIRST BSD license file in the root directory of */
 /* the project.                                                               */
@@ -8,10 +8,10 @@
 #pragma once
 
 #include <memory>
-#include <regex>
 #include <utility>
 
-#include <mockdata/MockHooks.h>
+#include <frc/simulation/DriverStationSim.h>
+#include <hal/simulation/MockHooks.h>
 
 #include "ErrorConfirmer.h"
 #include "frc2/command/CommandGroupBase.h"
@@ -21,7 +21,6 @@
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 #include "make_vector.h"
-#include "simulation/DriverStationSim.h"
 
 namespace frc2 {
 class CommandTestBase : public ::testing::Test {