tool: remove dead code

Add a debug assertion to verify protocols included/excluded in a set
are always tokenized.

Follow-up to commit 677266c.

Closes #9576

src/tool_paramhlp.c

@@ -271,6 +271,8 @@ static size_t protoset_index(const char * const *protoset, const char *proto)
 {
   const char * const *p = protoset;
 
+  DEBUGASSERT(proto == proto_token(proto));     /* Ensure it is tokenized. */
+
   for(; *p; p++)
     if(proto == *p)
       break;