Damage of cached hte_hash values for HTs leads to undefined behavior

Low budget memory modules affected by soft errors Broken hte_hash value indirectly but drastically changes logic of code. Tor should to fix damaged hte_hash values or assert on failure. Or to be ready for such damages so it wasn't reason of another looks alike random bugs. For example usage of HT_NEXT(_RMV) for iterating over hash table with broken hash values leads to shortage or infinite loops.