Add JNI binding to suppress driver station error/warning messages (#2200)

This is to allow suppressing an ugly stack trace/error message in a unit test in #2197. It doesn't support the full HALSIM_SetSendError callback stuff (i.e. you can only suppress, not intercept, stack traces with this).

hal/src/main/native/sim/jni/DriverStationDataJNI.cpp

@@ -1,5 +1,5 @@
 /*----------------------------------------------------------------------------*/
-/* Copyright (c) 2018 FIRST. All Rights Reserved.                             */
+/* Copyright (c) 2018-2019 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.                                                               */
@@ -14,6 +14,7 @@
 #include "CallbackStore.h"
 #include "edu_wpi_first_hal_sim_mockdata_DriverStationDataJNI.h"
 #include "mockdata/DriverStationData.h"
+#include "mockdata/MockHooks.h"
 
 using namespace wpi::java;
 
@@ -446,6 +447,25 @@ Java_edu_wpi_first_hal_sim_mockdata_DriverStationDataJNI_notifyNewData
   HALSIM_NotifyDriverStationNewData();
 }
 
+/*
+ * Class:     edu_wpi_first_hal_sim_mockdata_DriverStationDataJNI
+ * Method:    setSendError
+ * Signature: (Z)V
+ */
+JNIEXPORT void JNICALL
+Java_edu_wpi_first_hal_sim_mockdata_DriverStationDataJNI_setSendError
+  (JNIEnv*, jclass, jboolean shouldSend)
+{
+  if (shouldSend) {
+    HALSIM_SetSendError(nullptr);
+  } else {
+    HALSIM_SetSendError([](HAL_Bool isError, int32_t errorCode,
+                           HAL_Bool isLVCode, const char* details,
+                           const char* location, const char* callStack,
+                           HAL_Bool printMsg) { return 1; });
+  }
+}
+
 /*
  * Class:     edu_wpi_first_hal_sim_mockdata_DriverStationDataJNI
  * Method:    resetData