Update base for Update on "Rename ModuleLinear -> ModuleAddMul"

In export_program, the `ModuleLinear` is a decomposed add mul. Renaming it to addmul, so that we can add a ModuleLinear that calls nn.Linear for backend program-data separation testing.

Differential Revision: [D73679750](https://our.internmc.facebook.com/intern/diff/D73679750/)

[ghstack-poisoned]

Author: lucylq