Pin all TOSA components to v0.80 (#1701)

Summary:
- Pin TOSA serialization_lib to `branch` v0.80
- Pin TOSA reference_model to `branch` v0.80
- Fix any affected changes

I accidentally changed the serialization_lib hash in this patch: https://github.com/pytorch/executorch/commit/99f912ac8475bbe9546b133ac26b06ed7a352757#diff-099ad350604656a18b4146f6f297241b6d294a0650882968029fb1f574267f0d

Pin all TOSA components to `branch` v0.80. Hope we can have a stable development setup for a certain period of time.

Previously, serialization_lib was pinned to a `tag`, reference_model was pinned to a `branch`. There can be a debate about whether to use tag or branch but at least I think we should make them consistent.

Serialization_lib: https://review.mlplatform.org/plugins/gitiles/tosa/serialization_lib/
Reference_model: https://review.mlplatform.org/plugins/gitiles/tosa/reference_model/

Pull Request resolved: https://github.com/pytorch/executorch/pull/1701

Reviewed By: cccclai

Differential Revision: D53112872

Pulled By: guangy10

fbshipit-source-id: 77baf691735f8992507556f117932229c253ecfd