SDL2: Write battery file information before issueing RESET_COMMAND

Before performing the GB reset, we should perform a GB_save_battery.

Otherwise, resetting the emulation will kill ("kill" as in simply don't
write them into the .sav) all changes made to the battery save since
sameboy was started.

SDL/main.c

@@ -302,6 +302,7 @@ static bool handle_pending_command(void)
         }
             
         case GB_SDL_RESET_COMMAND:
+            GB_save_battery(&gb, battery_save_path_ptr);
             return true;
             
         case GB_SDL_NO_COMMAND: