Such a recursive call occurs when sorting the array of Child SAs inside
an IKE SA that causes comparisons of the child configs and their
proposals, which in turn creates a merged array of all transform types
and that uses array_sort() and array_bsearch().
Closesstrongswan/strongswan#2926
Fixes: 8e7f379f71 ("ike-sa: Sort CHILD_SAs by CPU ID")