fix dynamic_shapes spec for moco (#148772) (#2601)
Summary:
Pull Request resolved: https://github.com/pytorch/benchmark/pull/2601
Fixes https://github.com/pytorch/pytorch/issues/148333
X-link: https://github.com/pytorch/pytorch/pull/148772
Approved by: https://github.com/yushangdi, https://github.com/desertfire
Reviewed By: yushangdi, angelayi
Differential Revision: D71412041
fbshipit-source-id: c5d2bf63539534d0e660da9ea882be1984f693ec
