The tests intentionally allocate a very large string. Hence, for some memory limited configurations, it is perfectly reasonable for the test to throw an Out Of Memory error.
Created attachment 380692 [details] propose patch.
Comment on attachment 380692 [details] propose patch. r=me
Thanks for the review. Landed in r250995: <http://trac.webkit.org/r250995>.
<rdar://problem/56174573>