Method destroy

scripts/perf-counters/src/thread-local.h:311–318

  static bool isNull() { return s_singleton == nullptr; }

  static void destroy() {
    assert(!s_singleton || s_singleton == (T*)&s_storage);
    T* p = s_singleton;
    if (p) {
      T::Delete(p);
      s_singleton = nullptr;
    }
  }

  T *operator->() const {
    return getNoCheck();