[Core ML] Support enumerated input shapes (#74441)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/74441
For xirp based segmentation models, we want to support enumerated input shapes. This allows us to support both landscape and portrait mode images without sacrificing the performance. P488118264
ghstack-source-id: 151736964
Test Plan: `buck run coreml:xirp -- --model="/home/taox/xirp/xirp_20a.pt" --out="/home/taox/xirp/xirp_20a_coreml_enumerated.ptl"`
Reviewed By: mcr229
Differential Revision: D34803184
fbshipit-source-id: c462c0783846a1489ca7ce4d5a654aa6927c9c44
(cherry picked from commit 67d418c97531daaf3d03d1000ca4a4ff60de2a95)
