Bug#11792: Check all of status code, to catch a crash as a failure
mtr_cases.pl:
  Code cleanup for skipped/disabled handling
mtr_process.pl:
  In debug mode, report if mysqladmin did not at least
  make the server stop listening to the port.
  Increased the time waiting for terminating to 20 seconds,
  to wait for really slow slave shutdown.
  Added call to start_reap_all(), to avoid zombies.
mtr_report.pl:
  Removed prototype for unused function mtr_report_test_disabled()


mysql-test/lib/mtr_report.pl:
  Removed prototype for unused function mtr_report_test_disabled()
mysql-test/lib/mtr_cases.pl:
  Code cleanup for skipped/disabled handling
mysql-test/lib/mtr_process.pl:
  Bug#11792: Check all of status code, to catch a crash as a failure