This routine documented that "iterations" would use a default value if
set to 0 by the caller. However, the iteration should always be set by
the caller to a value strictly more than 0, as documented by an
assertion.
Oversight in b577743000cd, that has made the iteration count of SCRAM
configurable.
Author: Matheus Alcantara
Discussion: https://postgr.es/m/ac858943-4743-44cd-b4ad-08a0c10cbbc8@gmail.com
Backpatch-through: 16
7b2690a571