Small updates before patch submit.


client/mysqltest.c:
  allow --valgrind option to mysqltest so one can be able to detect
  whether the test is running under valgrind by having $VALGRIND_TEST,
  similar to BIG_TEST, in the test file.
mysql-test/mysql-test-run.pl:
  If the test suite is running under valgrind start mysqltest with --valgrind
  to inform that we run valgrind. mysqltest will provide $VALGRIND_TEST for the
  test cases.
mysql-test/r/events_bugs.result:
  update result
mysql-test/r/events_scheduling.result:
  update result
mysql-test/t/events.test:
  Increase times or the test will fail under valgrind
mysql-test/t/events_bugs.test:
  Increase times or the test will fail under valgrind
mysql-test/t/events_scheduling.test:
  Remove faulty test
  Disable the test case for valgrind
sql/event_data_objects.cc:
  count the number of executions
sql/event_data_objects.h:
  flags is not used at all
  add execution_count to count the number of executions
sql/event_db_repository.cc:
  Initialize wherever needed.
  Add a comment regarding valgrind warning.
sql/event_queue.cc:
  more debug info in the trace log
sql/event_scheduler.cc:
  Use macro COND_STATE_WAIT() in all cases we need waiting
  on condition. Hence, we can trace locking, attemption to lock
  and more with SHOW SCHEDULER STATUS
sql/event_scheduler.h:
  Change the declaration of cond_wait to accept THD
sql/events.cc:
  fix memory leak. Destroy event_queue
mysql-test/include/not_valgrind.inc:
  New BitKeeper file ``mysql-test/include/not_valgrind.inc''
mysql-test/r/not_valgrind.require:
  New BitKeeper file ``mysql-test/r/not_valgrind.require''