Test for STDERR from Qpsmtpd::Address->new(), and correct the failure

which was causing noisy tests.
I was about to ask the same question. The tests make it seem like new() is expected to return '<>'.  Until recently the tests were testing the output of ->format().  I haven't quite pinpointed when this changed (or at least became less obvious), but it looks like @msimerson has bee touching those tests recently fwiw :)