Fix static_assert for C++20 (#1628)

Summary:
This is a follow-up on https://github.com/facebook/folly/issues/1594

Pull Request resolved: https://github.com/facebook/folly/pull/1628

Differential Revision: D30179861

Pulled By: yfeldblum

fbshipit-source-id: 8949cd95e089a14f0ee63b784cecebe93c473607

folly/concurrency/CacheLocality.h

@@ -259,7 +259,9 @@ struct AccessSpreader : private detail::AccessSpreaderBase {
  private:
   struct GlobalState : detail::AccessSpreaderBase::GlobalState {};
   static_assert(
-      std::is_trivial<GlobalState>::value || kCpplibVer, "not trivial");
+      is_constexpr_default_constructible_v<GlobalState> &&
+          std::is_trivially_destructible<GlobalState>::value,
+      "unsuitable for global state");
 
  public:
   FOLLY_EXPORT static GlobalState& state() {