BUG#49978: Replication tests don't clean up replication state at the end

Major replication test framework cleanup. This does the following:
 - Ensure that all tests clean up the replication state when they
   finish, by making check-testcase check the output of SHOW SLAVE STATUS.
   This implies:
    - Slave must not be running after test finished. This is good
      because it removes the risk for sporadic errors in subsequent
      tests when a test forgets to sync correctly.
    - Slave SQL and IO errors must be cleared when test ends. This is
      good because we will notice if a test gets an unexpected error in
      the slave threads near the end.
    - We no longer have to clean up before a test starts.
 - Ensure that all tests that wait for an error in one of the slave
   threads waits for a specific error. It is no longer possible to
   source wait_for_slave_[sql|io]_to_stop.inc when there is an error
   in one of the slave threads. This is good because:
    - If a test expects an error but there is a bug that causes
      another error to happen, or if it stops the slave thread without
      an error, then we will notice.
    - When developing tests, wait_for_*_to_[start|stop].inc will fail
      immediately if there is an error in the relevant slave thread.
      Before this patch, we had to wait for the timeout.
 - Remove duplicated and repeated code for setting up unusual replication
   topologies. Now, there is a single file that is capable of setting
   up arbitrary topologies (include/rpl_init.inc, but
   include/master-slave.inc is still available for the most common
   topology). Tests can now end with include/rpl_end.inc, which will clean
   up correctly no matter what topology is used. The topology can be
   changed with include/rpl_change_topology.inc.
 - Improved debug information when tests fail. This includes:
    - debug info is printed on all servers configured by include/rpl_init.inc
    - User can set $rpl_debug=1, which makes auxiliary replication files
      print relevant debug info.
 - Improved documentation for all auxiliary replication files. Now they
   describe purpose, usage, parameters, and side effects.
 - Many small code cleanups:
    - Made have_innodb.inc output a sensible error message.
    - Moved contents of rpl000017-slave.sh into rpl000017.test
    - Added mysqltest variables that expose the current state of
      disable_warnings/enable_warnings and friends.
    - Too many to list here: see per-file comments for details.

mysql-test/suite/rpl/r/rpl_rotate_logs.result

@@ -1,5 +1,3 @@
-drop table if exists t1, t2, t3, t4;
-drop table if exists t1, t2, t3, t4;
 start slave;
 Got one of the listed errors
 start slave;
@@ -14,9 +12,9 @@ create temporary table temp_table (a char(80) not null);
 insert into temp_table values ("testing temporary tables");
 create table t1 (s text);
 insert into t1 values('Could not break slave'),('Tried hard');
-Master_Log_File	master-bin.000001
-Relay_Master_Log_File	master-bin.000001
-Checking that both slave threads are running.
+Master_Log_File = 'master-bin.000001'
+Relay_Master_Log_File = 'master-bin.000001'
+include/check_slave_is_running.inc
 select * from t1;
 s
 Could not break slave
@@ -38,8 +36,7 @@ drop table temp_table, t3;
 insert into t2 values(1234);
 set insert_id=1234;
 insert into t2 values(NULL);
-set global sql_slave_skip_counter=1;
-start slave;
+include/wait_for_slave_sql_error_and_skip.inc [errno=1062]
 purge master logs to 'master-bin.000002';
 show master logs;
 Log_name	master-bin.000002
@@ -57,9 +54,9 @@ show binary logs;
 Log_name	File_size
 master-bin.000003	#
 insert into t2 values (65);
-Master_Log_File	master-bin.000003
-Relay_Master_Log_File	master-bin.000003
-Checking that both slave threads are running.
+Master_Log_File = 'master-bin.000003'
+Relay_Master_Log_File = 'master-bin.000003'
+include/check_slave_is_running.inc
 select * from t2;
 m
 34
@@ -85,9 +82,9 @@ master-bin.000005	#	<Binlog_Do_DB>	<Binlog_Ignore_DB>
 select * from t4;
 a
 testing temporary tables part 2
-Master_Log_File	master-bin.000005
-Relay_Master_Log_File	master-bin.000005
-Checking that both slave threads are running.
+Master_Log_File = 'master-bin.000005'
+Relay_Master_Log_File = 'master-bin.000005'
+include/check_slave_is_running.inc
 lock tables t3 read;
 select count(*) from t3 where n >= 4;
 count(*)
@@ -102,3 +99,5 @@ show binlog events in '';
 ERROR HY000: Error when executing command SHOW BINLOG EVENTS: Could not find target log
 purge master logs before now();
 End of 5.0 tests
+include/stop_slave.inc
+CHANGE MASTER TO MASTER_HOST = '';