Remove debug print statements from zcpu opcode dispatch

The exception that follows provides the context, so these prints are redundant.

src/mudlib/zmachine/zcpu.py

@@ -62,8 +62,6 @@ class ZCpu:
         except IndexError:
             opcode_decl = None
         if not opcode_decl:
-            cls, num = opcode_class, opcode_number
-            print(f"DEBUG: Illegal opcode class={cls} num={num}")
             raise ZCpuIllegalInstruction
 
         # If the opcode declaration is a sequence, we have extra
@@ -84,8 +82,6 @@ class ZCpu:
             elif opcode_decl[1] <= self._memory.version:
                 opcode_func = opcode_decl[0]
             else:
-                cls, num = opcode_class, opcode_number
-                print(f"DEBUG: Illegal opcode class={cls} num={num}")
                 raise ZCpuIllegalInstruction
 
         # The following is a hack, based on our policy of only