Post merge fixes: close any open statement before
the change user command and fix test case output.
client/mysqltest.c:
Close an open statement since it won't work after a change_user command.
mysql-test/r/change_user.result:
Fixed test case output.
mysql-test/t/change_user.test:
Fix test case output to return 1 or 0.
The problem is that currently there is no way to test the behavior
of the mysql_change_user() function using the mysqltest suite because
there is no internal command for it.
The solution is to introduce a change_user command that can be used
to test aspects of the MySQL client function mysql_change_user().
client/mysqltest.c:
Add change_user command to mysqltest.
mysql-test/r/mysqltest.result:
Add test case result for change_user command
mysql-test/t/mysqltest.test:
Add test case for change_user command
mysql-test/r/change_user.result:
Add new file with test case results for bugs 20023 and 31418.
mysql-test/t/change_user.test:
Add new file with test cases for bugs 20023 and 31418.
