message: Fix setting out_mtypes in MemoryTypesForNode
  Clear hostmem_attr vector before populating it with indices from "_output_hostmem" attribute so that it doesn't contain indices from "_input_hostmem" attribute.
diff: @@ -161,6 +161,7 @@ Status MemoryTypesForNode(const OpRegistryInterface* op_registry,
  }
  }
  }
  + hostmem_attr.clear();
  if (TryGetNodeAttr(ndef, "_output_hostmem", &hostmem_attr)) {
  for (int32 i : hostmem_attr) {
  if (0 <= i && i < out_mtypes->size()) {
  