Summary:
1. Add capability to clang frontend to replace some function calls with another SIL code based on `__deprecated__` attribute.
2. Given this capability, use those attributes for shared_ptr getters to generate `Sil.Load` instruction instead of method call
3. Add test that mimics shared_ptr model, but it doesn't have that much scary C++ templated code
Reviewed By: jvillard, jberdine
Differential Revision: D3729176
fbshipit-source-id: 2a330d5
Andrzej Kotulski