message: Replace a defensive check with TF_RET_CHECK
diff: @@ -94,11 +94,9 @@ Status PickDeviceForXlaImpl(absl::Span<const string> device_names,
  absl::flat_hash_set<absl::string_view> device_names_set;
  for (absl::string_view device_name : device_names) {
  - if (!device_name.empty()) {
  - // TODO(sanjoy): Figure out if this is necessary.
  + TF_RET_CHECK(!device_name.empty());
  device_names_set.insert(device_name);
  }
  - }
  absl::optional<absl::string_view> maybe_gpu_device;
  absl::optional<absl::string_view> maybe_cpu_device;
  