MDEV-17491 post-fix: GCC 7 -Wclass-memaccess

commit 3a37644a added a non-POD
member buf_page_info_t::id, and thus GCC 7 or later would complain
about a memset() call. Let my_malloc fill the memory for us.

storage/innobase/handler/i_s.cc

@@ -4612,15 +4612,13 @@ static int i_s_innodb_fill_buffer_lru(THD *thd, TABLE_LIST *tables, Item *)
 
 	/* Print error message if malloc fail */
 	info_buffer = (buf_page_info_t*) my_malloc(PSI_INSTRUMENT_ME,
-		lru_len * sizeof *info_buffer, MYF(MY_WME));
+		lru_len * sizeof *info_buffer, MYF(MY_WME | MY_ZEROFILL));;
 
 	if (!info_buffer) {
 		status = 1;
 		goto exit;
 	}
 
-	memset(info_buffer, 0, lru_len * sizeof *info_buffer);
-
 	/* Walk through Pool's LRU list and print the buffer page
 	information */
 	bpage = UT_LIST_GET_LAST(buf_pool.LRU);