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/t/rpl_binlog_errors.test

@@ -14,9 +14,9 @@
 # 
 # Test cases are documented inline.
 
--- source include/master-slave.inc
 -- source include/have_innodb.inc
 -- source include/have_debug.inc
+-- source include/master-slave.inc
 
 -- echo #######################################################################
 -- echo ####################### PART 1: MASTER TESTS ##########################
@@ -295,7 +295,8 @@ DROP TABLE t5;
 ###            failure to write the rotate event.
 
 # restart the server so that we have binlog again
---source include/restart_mysqld.inc
+--let $rpl_server_number= 1
+--source include/rpl_restart_server.inc
 
 # +d,fault_injection_openning_index => injects fault on MYSQL_BIN_LOG::open_index_file
 SET GLOBAL debug="+d,fault_injection_openning_index";
@@ -316,7 +317,8 @@ DELETE FROM t2;
 DROP TABLE t5;
 
 # restart the server so that we have binlog again
--- source include/restart_mysqld.inc
+--let $rpl_server_number= 1
+--source include/rpl_restart_server.inc
 
 -- echo ###################### TEST #12
 
@@ -342,7 +344,8 @@ DELETE FROM t2;
 DROP TABLE t5;
 
 # restart the server so that we have binlog again
--- source include/restart_mysqld.inc
+--let $rpl_server_number= 1
+--source include/rpl_restart_server.inc
 
 ## clean up
 SET GLOBAL debug= @old_debug;
@@ -359,9 +362,7 @@ RESET MASTER;
 -- echo #######################################################################
 
 ### setup
--- connection master
-# master-slave-reset starts the slave automatically
--- source include/master-slave-reset.inc
+--source include/rpl_reset.inc
 -- connection slave
 
 # slave suppressions
@@ -404,12 +405,9 @@ call mtr.add_suppression("Can't generate a unique log-filename .*");
 -- source include/io_thd_fault_injection.inc
 
 ### clean up
--- disable_warnings
--- source include/stop_slave.inc
--- enable_warnings
+-- source include/stop_slave_sql.inc
 SET GLOBAL debug=@old_debug;
 RESET SLAVE;
 RESET MASTER;
--- source include/start_slave.inc
--- connection master
--- source include/master-slave-end.inc
+--let $rpl_only_running_threads= 1
+--source include/rpl_end.inc