Up-merge from 5.0; adds test for innodb bug 34286 (but no code changes).

mysql-test/r/innodb-autoinc-optimize.result

+drop table if exists t1;
+create table t1(a int not null auto_increment primary key) engine=innodb;
+insert into t1 set a = -1;
+optimize table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	optimize	status	OK

mysql-test/t/innodb-autoinc-optimize.test

+-- source include/have_innodb.inc
+# embedded server ignores 'delayed', so skip this
+-- source include/not_embedded.inc
+
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+
+#
+# Bug 34286
+#
+create table t1(a int not null auto_increment primary key) engine=innodb;
+insert into t1 set a = -1;
+# NOTE: The database needs to be shutdown and restarted (here) for
+# the test to work. It's included for reference only.
+optimize table t1;