Write max_align_v and max_align_t using C++14
Write max_align_v and max_align_t using C++14

Summary:
[Folly] Write `max_align_v` and `max_align_t` using C++14 `constexpr` syntax v.s. using the recursive approach required by C++11.

Instantiates fewer function templates in each translation unit.

Reviewed By: Orvid

Differential Revision: D19229027

fbshipit-source-id: e01ac2d428a42a6e4f86f55f5528c42f9b70cd9f

facebook/folly,facebook/folly,facebook/folly,facebook/folly,facebook/folly