Stateless tests: Keep an DNS error free log

tests/queries/0_stateless/00965_shard_unresolvable_addresses.sql

@@ -1,2 +1,5 @@
 SELECT count() FROM remote('127.0.0.1,localhos', system.one); -- { serverError 198 }
 SELECT count() FROM remote('127.0.0.1|localhos', system.one);
+
+-- Clear cache to avoid future errors in the logs
+SYSTEM DROP DNS CACHE

tests/queries/0_stateless/01083_expressions_in_engine_arguments.sql

@@ -68,3 +68,6 @@ INSERT INTO buffer VALUES (1);
 --                                                     |                              |-> file (1)
 --                                                     |-> remote(127.0.0.2) --> ...
 SELECT sum(n) from rich_syntax;
+
+-- Clear cache to avoid future errors in the logs
+SYSTEM DROP DNS CACHE

tests/queries/0_stateless/01372_remote_table_function_empty_table.sql

@@ -1 +1,4 @@
 SELECT * FROM remote('127..2', 'a.'); -- { serverError 36 }
+
+-- Clear cache to avoid future errors in the logs
+SYSTEM DROP DNS CACHE