Fix: M112 calling kill from interrupt (#9923)

Fix #9906

Marlin/src/HAL/HAL_AVR/MarlinSerial.cpp

@@ -81,6 +81,8 @@
 
   #if ENABLED(EMERGENCY_PARSER)
 
+    bool killed_by_M112; // = false
+
     #include "../../module/stepper.h"
 
     // Currently looking for: M108, M112, M410
@@ -155,7 +157,7 @@
                 wait_for_user = wait_for_heatup = false;
                 break;
               case state_M112:
-                kill(PSTR(MSG_KILLED));
+                killed_by_M112 = true;
                 break;
               case state_M410:
                 quickstop_stepper();

Marlin/src/HAL/HAL_AVR/MarlinSerial.h

@@ -94,6 +94,10 @@
     extern ring_buffer_pos_t rx_max_enqueued;
   #endif
 
+  #if ENABLED(EMERGENCY_PARSER)
+    extern bool killed_by_M112;
+  #endif
+
   class MarlinSerial { //: public Stream
 
     public: