Bugfix: Multiple M77 no longer increment the print counter

Marlin/printcounter.cpp

     PrintCounter::debug(PSTR("stop"));
   #endif
 
+  if (!this->isRunning()) return;
   super::stop();
+
   this->data.finishedPrints++;
   this->data.printTime += this->deltaDuration();
   this->saveStats();