WL#4189 Only kill process that hasn't yet finished at end of mtr.pl. Improve debug printout

mysql-test/lib/My/SafeProcess.pm

@@ -66,9 +66,11 @@ END {
   for my $proc (values %running){
     if ( $proc->is_child($$) ){
       #print "Killing: $proc\n";
+      if ($proc->wait_one(0)){
 	$proc->kill();
       }
     }
+  }
 }
 
 
@@ -315,7 +317,7 @@ sub start_kill {
     $ret= system($safe_kill, $pid) >> 8;
     if (IS_CYGWIN and $ret == 3)
     {
-      print "safe_process is gone, kickstart the fake process\n";
+      print "safe_process is gone, kickstart the fake process, $self\n";
       if (kill(15, $self->{SAFE_PID}) != 1){
 	print STDERR "Failed to kickstart the fake process\n";
       }