HashEnumerator is converted to a MemorySafeEnumerator
HashEnumerator is converted to a MemorySafeEnumerator

Fixes HashEnumerator. The MemorySafeEnumerator base class is now used.
HashEnumerator used to implement an old enumerator not following the new
memory model pattern.
renames _internalEnumerator to _hashEnumerator

sestoft/C5,nbasakuragi/C5