PROBLEM:
Test cases that execute ndb_backup, leaves the backup directory uncleaned
and makes other parallel test cases in mtr to run with limited memory.
This may also lead to random "out of disk" issues.

FIX:
1)Include files "backup_restore_setup.inc" and
"backup_restore_cleanup.inc" were added to all the test cases that does
ndb_restore and ndb_backup.
2)"ndb_backup_restore_setup.inc" contains the script to find the binary for
ndb_restore. Prior to this bug, this code was inside "mysql-test-run.pl". But, now
it is moved to make sure that developer, who writes test case with ndb_restore
and ndb_backup in future must include "backup_restore_setup.inc" and
"backup_restore_cleanup.inc" in their test cases.
3)Command line arguments for ndb_restore that are common across all tests
were moved to one place in "backup_restore_setup.inc". This reduces the
code duplication in test suite.
4)"backup_restore_cleanup.inc" has to be added to the end of all
test cases that does ndb_backup and ndb_restore.It cleans up all the changes
done by "backup_restore_setup.inc" and deletes the backup directory.
5)New validation is added to "check-testcase.test". This will check if the
backup directory exist, after executing each test case and fails the test case
if the backup directory is not removed by the test case.