[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

wpilibc/src/test/native/cpp/simulation/SimInitializationTest.cpp

@@ -0,0 +1,47 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2018-2020 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include <hal/HAL.h>
+
+#include "frc/simulation/AccelerometerSim.h"
+#include "frc/simulation/AnalogGyroSim.h"
+#include "frc/simulation/AnalogInSim.h"
+#include "frc/simulation/AnalogOutSim.h"
+#include "frc/simulation/AnalogTriggerSim.h"
+#include "frc/simulation/DIOSim.h"
+#include "frc/simulation/DigitalPWMSim.h"
+#include "frc/simulation/DriverStationSim.h"
+#include "frc/simulation/EncoderSim.h"
+#include "frc/simulation/PCMSim.h"
+#include "frc/simulation/PDPSim.h"
+#include "frc/simulation/PWMSim.h"
+#include "frc/simulation/RelaySim.h"
+#include "frc/simulation/RoboRioSim.h"
+#include "frc/simulation/SPIAccelerometerSim.h"
+#include "gtest/gtest.h"
+
+using namespace frc::sim;
+
+TEST(SimInitializationTests, TestAllInitialize) {
+  HAL_Initialize(500, 0);
+  AccelerometerSim acsim{0};
+  AnalogGyroSim agsim{0};
+  AnalogInSim aisim{0};
+  AnalogOutSim aosim{0};
+  AnalogTriggerSim atsim{0};
+  DigitalPWMSim dpsim{0};
+  DIOSim diosim{0};
+  DriverStationSim dssim;
+  (void)dssim;
+  EncoderSim esim{0};
+  PCMSim pcmsim{0};
+  PDPSim pdpsim{0};
+  PWMSim pwmsim{0};
+  RelaySim rsim{0};
+  RoboRioSim rrsim{0};
+  SPIAccelerometerSim sasim{0};
+}