Simplified away CONNECT::extra_port

Part of MDEV-19515 - Improve connect speed

sql/mysqld.cc

@@ -6365,10 +6365,7 @@ void handle_accepted_socket(MYSQL_SOCKET new_sock, MYSQL_SOCKET sock)
   }
 
   if (mysql_socket_getfd(sock) == mysql_socket_getfd(extra_ip_sock))
-  {
-    connect->extra_port= 1;
     connect->scheduler= extra_thread_scheduler;
-  }
   create_new_thread(connect);
 }
 

sql/sql_class.cc

@@ -726,7 +726,6 @@ THD::THD(my_thread_id id, bool is_wsrep_applier)
   event_scheduler.data= 0;
   event_scheduler.m_psi= 0;
   skip_wait_timeout= false;
-  extra_port= 0;
   catalog= (char*)"std"; // the only catalog we have for now
   main_security_ctx.init();
   security_ctx= &main_security_ctx;

sql/sql_class.h

@@ -3059,7 +3059,6 @@ class THD: public THD_count, /* this must be first */
   uint8      password; /* 0, 1 or 2 */
   uint8      failed_com_change_user;
   bool       slave_thread;
-  bool       extra_port;                        /* If extra connection */
   bool	     no_errors;
 
   /**

sql/sql_connect.cc

@@ -1521,7 +1521,6 @@ THD *CONNECT::create_thd(THD *thd)
                            thd->net.vio->type == VIO_TYPE_SOCKET ?
                            my_localhost : 0;
 
-  thd->extra_port=         extra_port;
   thd->scheduler=          scheduler;
   thd->real_id=            real_id;
   DBUG_RETURN(thd);

sql/sql_connect.h

@@ -35,7 +35,6 @@ class CONNECT : public ilink {
   scheduler_functions *scheduler;
   my_thread_id thread_id;
   pthread_t    real_id;
-  bool extra_port;
 
   /* Own variables */
   bool thread_count_incremented;
@@ -43,7 +42,6 @@ class CONNECT : public ilink {
 
   CONNECT()
     :vio(0), scheduler(thread_scheduler), thread_id(0), real_id(0),
-    extra_port(0),
     thread_count_incremented(0), prior_thr_create_utime(0)
   {
   };