[PyTorch][Edge] share readArchiveAndTensors between mobile and jit (#57098)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57098
1. Separate `readArchiveAndTensors()` from `jit/import.cpp` to a new file `jit/import_read.cpp`.
2. Use `readArchiveAndTensors()` in `mobile/import.cpp`
ghstack-source-id: 127703081
3. Add a util function in cpp that could read .pkl files directly instead of loading the entire module
Test Plan: CI
Reviewed By: raziel, iseeyuan
Differential Revision: D28052193
fbshipit-source-id: c8d57f3270bdcf2e52a32f7c111899bd5da7cac2
