suppressed leaks show up in leak count for -no_check_leaks

_From [derek.br...@gmail.com](https://code.google.com/u/117968039472581148324/) on June 29, 2010 09:56:49_

I have leak callstacks off by default to save memory but there is a problem.
Leak suppression can only happen when callstacks are available:
so by default (i.e., -no_check_leaks) they will not be suppressed
and will show up in the leak count error summary which is not
ideal. This can be seen in the winthreads test with its
(forthcoming: DR issue #286) default-suppress leak.

Perhaps leak callstacks should just be on by default.

_Original issue: http://code.google.com/p/drmemory/issues/detail?id=8_