Fix for BUG##24415: Instance manager test im_daemon_life_cycle

fails randomly.

The problem was that the test case used command line tool (mysql)
without specifying connect_timeout argument. In some cases,
this lead to hanging of the test case.

The fix is to specify --connect_timeout=1 when starting mysql.

Also, the patch contains polishing and various cleanups to simplify
analyzing of the problems further.

The patch affects only test suite, no server codebase has been
touched.

mysql-test/lib/mtr_process.pl

@@ -937,6 +937,12 @@ sub check_expected_crash_and_restart($)
       }
     }
   }
+
+  if ($::instance_manager->{'spawner_pid'} eq $ret_pid)
+  {
+    return;
+  }
+
   mtr_warning("check_expected_crash_and_restart couldn't find an entry for pid: $ret_pid");
 
 }