Start using the new FRC compiler define (#797)

Remove all definitions from the MockData headers when in simulation mode.
Add a constexpr IsReal and IsSimulation in RobotBase.

hal/src/main/native/include/MockData/RelayData.h

@@ -7,6 +7,8 @@
 
 #pragma once
 
+#ifndef __FRC_ROBORIO__
+
 #include "HAL/HAL.h"
 #include "NotifyListener.h"
 
@@ -54,3 +56,5 @@ void HALSIM_RegisterRelayAllCallcbaks(int32_t index,
 #ifdef __cplusplus
 }  // extern "C"
 #endif
+
+#endif