[wpilibc] Prevent StopMotor from terminating robot during MotorSafety check (#4038)

- Nothing else in that function can throw, so protecting StopMotor should be sufficient
- Fixes #4036

wpilibc/src/main/native/include/frc/MotorSafety.h

@@ -91,6 +91,12 @@ class MotorSafety {
   static void CheckMotors();
 
   virtual void StopMotor() = 0;
+
+  /**
+   * The return value from this method is printed out when an error occurs
+   *
+   * This method must not throw!
+   */
   virtual std::string GetDescription() const = 0;
 
  private: