auto_increment.test, auto_increment.result:

  Drop t2 in the beginning.
  ,

mysql-test/r/auto_increment.result

 drop table if exists t1;
+drop table if exists t2;
 SET SQL_WARNINGS=1;
 create table t1 (a int not null auto_increment,b int, primary key (a)) engine=myisam auto_increment=3;
 insert into t1 values (1,1),(NULL,3),(NULL,4);

mysql-test/t/auto_increment.test

@@ -3,6 +3,7 @@
 #
 --disable_warnings
 drop table if exists t1;
+drop table if exists t2;
 --enable_warnings
 SET SQL_WARNINGS=1;