Do not call optimizations within freezing API (#38499)
Summary:
This patch removes call to run optimizations within freezing API.
Only dead code elimination is invoked to clean up the frozen module.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/38499
Reviewed By: eellison
Differential Revision: D21579607
Pulled By: bzinodev
fbshipit-source-id: a6231754fea89296a3dcf07b5e37a1c43cb8d5dd
