Mark some extended commands as no-fuzzer

... instead of checking the fuzzer being on in the commands themselves.

include/func_tab.h

@@ -12,6 +12,7 @@
 #define WIZMODECMD   0x04 /* wizard-mode command */
 #define GENERALCMD   0x08 /* general command, does not take game time */
 #define CMD_NOT_AVAILABLE 0x10 /* recognized but non-functional (!SHELL,&c) */
+#define NOFUZZERCMD  0x20 /* fuzzer cannot execute this command */
 
 struct ext_func_tab {
     uchar key;