[phobos] Looks like more problems with the array append patches

[Walter Bright]

Thanks much for taking care of this. I'd also like a test case we can 
add to the test suite, so we can ensure it never happens again.

Steve Schveighoffer wrote:
> Through debugging Ellery Newcomer's test case (see http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=108685), I have found another bug in the array append patch.
>
>