Use std::is_nothrow_swappable under MSVC

Use std::is_nothrow_swappable under MSVC

Summary:
The current implementation didn't work for MSVC, as it tries to evaluate `noexcept` expressions in base class lists before the template is instantiated.
`std::is_nothrow_swappable` is coming in C++17, and MSVC already has it, so use it instead.

Reviewed By: yfeldblum

Differential Revision: D3724399

fbshipit-source-id: 7927584618a7870824b2e7242fcae562647f4ef4