SITL: added panic() method in scheduler

libraries/AP_HAL_AVR_SITL/Scheduler.cpp

@@ -192,4 +192,9 @@ void SITLScheduler::timer_event()
     _in_timer_proc = false;
 }
 
+void SITLScheduler::panic(const prog_char_t *errormsg) {
+    hal.console->println_P(errormsg);
+    for(;;);
+}
+
 #endif

libraries/AP_HAL_AVR_SITL/Scheduler.h

@@ -29,6 +29,7 @@ public:
     void     begin_atomic();
     void     end_atomic();
     void     reboot();
+    void     panic(const prog_char_t *errormsg);
 
     bool     interrupts_are_blocked(void) { return _nested_atomic_ctr != 0; }