Revert D32743881: [Core ML] Avoid recompiling models when the OS version is not changed
Test Plan: revert-hammer
Differential Revision:
D32743881 (https://github.com/pytorch/pytorch/commit/b97903abb8285cd7d7e102b799f09341b12ac249)
Original commit changeset: 2e94c6035520
fbshipit-source-id: 6cb05c414a23e15604b095c333a92ed8980092bd
