[wpilibc] Add mechanism to reset various global structures (#4007)

wpilibc/src/main/native/cpp/smartdashboard/SmartDashboard.cpp

@@ -29,11 +29,23 @@ struct Instance {
 };
 }  // namespace
 
-static Instance& GetInstance() {
-  static Instance instance;
+static std::unique_ptr<Instance>& GetInstanceHolder() {
+  static std::unique_ptr<Instance> instance = std::make_unique<Instance>();
   return instance;
 }
 
+static Instance& GetInstance() {
+  return *GetInstanceHolder();
+}
+
+#ifndef __FRC_ROBORIO__
+namespace frc::impl {
+void ResetSmartDashboardInstance() {
+  std::make_unique<Instance>().swap(GetInstanceHolder());
+}
+}  // namespace frc::impl
+#endif
+
 void SmartDashboard::init() {
   GetInstance();
 }