[3.13] gh-133131: Discover an appropriate iOS simulator rather than hard-coding iPhone SE 3rd gen (GH-133132) (#133173)

Determines a candidate simulator at runtime rather than hardcoding iPhone SE.
(cherry picked from commit 42b0b0667e67ff444a03d0e7b217e77f3aae535d)

Co-authored-by: Russell Keith-Magee <russell@keith-magee.com>