Multiple-result processing is required during the execution
of CALL statements for stored procedures, however the mysqlslap
client lacked that processing.



client/mysqlslap.c:
  Fixed bug #29985.
  1. Connection flags have been changed: the CLIENT_MULTI_STATEMENTS
  flag has been added.
  2. The run_task function has been modified to process multiple
  result sets.
mysql-test/t/mysqlslap.test:
  Added test case for bug #29985.
mysql-test/r/mysqlslap.result:
  Added test case for bug #29985.