Remove c++14-conditional constexpr (#30916)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/30916
These macros said "make it constexpr if we're in C++14". Since we're now always C++14, we can just say "constexpr" isntead.
ghstack-source-id: 96369584
Test Plan: waitforsandcastle
Differential Revision: D18869635
fbshipit-source-id: f41751e4e26fad6214ec3a98db2d961315fd73ff
