[COMMITTED 2.34 2/2] malloc: Improve aligned_alloc and calloc test coverage.

[Florian Weimer]

* Miguel Martín:

> Then, we only need to backport d141717 to glibc/2.39/master so
> all the commits are in upstream 2.39 before backporting them downstream
> to 2.34, right?

We don't need to backport this to 2.39, either.

Thanks,
Florian