Some of the test cases reference to binlog position and
these position numbers are written into result explicitly.
It is difficult to maintain if log event format changes. 

There are a couple of cases explicit position number appears, 
we handle them in different ways
A. 'CHANGE MASTER ...' with MASTER_LOG_POS or/and RELAY_LOG_POS options
   Use --replace_result to mask them.
B. 'SHOW BINLOG EVENT ...'
   Replaced by show_binlog_events.inc or wait_for_binlog_event.inc. 
   show_binlog_events.inc file's function is enhanced by given
   $binlog_file and $binlog_limit.
C. 'SHOW SLAVE STATUS', 'show_slave_status.inc' and 'show_slave_status2.inc'
   For the test cases just care a few items in the result of 'SHOW SLAVE STATUS',
   only the items related to each test case are showed.
   'show_slave_status.inc' is rebuild, only the given items in $status_items
   will be showed.
   'check_slave_is_running.inc' and 'check_slave_no_error.inc'
   and 'check_slave_param.inc' are auxiliary files helping
   to show running status and error information easily.