[Executorch] Revert compile optimizatin flags for op libs (#6618)

Reverting this change for now due to app size regression

Differential Revision: [D65336831](https://our.internmc.facebook.com/intern/diff/D65336831/)

ghstack-source-id: 251333393
Pull Request resolved: https://github.com/pytorch/executorch/pull/6609

Co-authored-by: Kimish Patel <kimishpatel@fb.com>