Fix t/perl/hash_attack.t to work with Perl 5.14.4, 5.16.3 etc, which contain a fix for CVE-2013-1667 (memory exhaustion with arbitrary hash keys). This resolves rt.perl.org #116863, from where the patch by Hugo van der Sanden was taken (with a minor edit in a comment by the committer).
Tested by the committer on Windows 7 x64 with VC++ 2010 using Perls 5.14.3, 5.14.4, 5.16.2 and 5.16.3-RC1, all against Apache 2.2.22.

git-svn-id: https://svn.apache.org/repos/asf/perl/modperl/trunk@1455340 13f79535-47bb-0310-9956-ffa450edef68