- fix for IM stopping routine;
  - polishing.


mysql-test/lib/mtr_process.pl:
  Polishing: make mtr_kill_process() more verbose in debug mode.
mysql-test/mysql-test-run.pl:
  1. Fix stopping of IM running as a daemon -- after death of the main IM
  process, we should wait for the IM angel to die.
  2. Polishing -- be more verbose in debug mode.