Removing the binlog-show-xid option as it was only a temporary solution until we have replace-regex which we have now.
That option was used to suppress the XID from the output of SHOW BINLOG EVENTS (to create a repeatable testsuite),
was available only in debug builds, and was explicitely marked as "may be removed in future versions" in mysqld --help.
Idea of the removal approved by the replication team.


mysql-test/extra/binlog_tests/binlog.test:
  use replace-regex to remove xid
mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test:
  use replace-regex to remove xid
mysql-test/mysql-test-run.pl:
  option removed
mysql-test/mysql-test-run.sh:
  option removed
sql/log_event.cc:
  no more need to hide XID in tests output as we have replace-regex
sql/log_event.h:
  no more need to hide XID in tests output as we have replace-regex
sql/mysqld.cc:
  no more need to hide XID in tests output as we have replace-regex