[caffe2] Refactor tensor serialization function (#53404)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/53404
This refactors `TensorSerializer::Serialize()` so that we have a separate
helper function for each data type.
This should make it slightly easier in the future to add new serialization
formats for specific data types.
ghstack-source-id: 124085413
Test Plan:
Confirmed the existing tests pass. This diff is not expected to have any
behavior changes.
Reviewed By: mraway, glamtechie
Differential Revision: D26658204
fbshipit-source-id: 232776262db6486ba845a7ba223e3987053dac27
