Replace std::random_shuffle with std::shuffle (#993)
Replace std::random_shuffle with std::shuffle (#993)

Summary:
- `std::random_shuffle` is deprecated in C++14 and removed in C++17.
- While `Folly` only depends on C++14, it should not hinder users from
  building in C++17 mode.
- To support users building with C++17 where `std::random_shuffle` is
  removed from the standard library, migrate the one call site to use
  `std::shuffle`.
Pull Request resolved: https://github.com/facebook/folly/pull/993

Reviewed By: Orvid

Differential Revision: D13620930

Pulled By: yfeldblum

fbshipit-source-id: 630d1125155e022f4b3e804f92c02ec663a86c3b

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