Merge branch 'mysql-5.6' into mysql-5.7

Author: dahlerlend

mysql-test/include/mtr_warnings.sql

@@ -1,4 +1,4 @@
--- Copyright (c) 2008, 2019, Oracle and/or its affiliates. All rights reserved.
+-- Copyright (c) 2008, 2020, Oracle and/or its affiliates. All rights reserved.
 --
 -- This program is free software; you can redistribute it and/or modify
 -- it under the terms of the GNU General Public License, version 2.0,
@@ -222,6 +222,10 @@ INSERT INTO global_suppressions VALUES
  ("==[0-9]*== Warning: invalid file descriptor -1 in syscall write()"),
  ("==[0-9]*== Warning: invalid file descriptor -1 in syscall read()"),
 
+ /* Suppress warnings caused by foreign clients, see Bug#31893901 */
+
+ ("IP address .* could not be resolved.*"),
+
  /*
    Transient network failures that cause warnings on reconnect.
    BUG#47743 and BUG#47983.