message: Update layout_optimizer_test.cc
  Place data format op on CPU:0.
diff: @@ -36,7 +36,7 @@ class LayoutOptimizerTest : public ::testing::Test {
  DeviceProperties device_properties;
  device_properties.set_type("GPU");
  device_properties.mutable_environment()->insert({"architecture", "6"});
  - virtual_cluster_.reset(new VirtualCluster({{"/GPU:0", device_properties}}));
  + virtual_cluster_.reset(new VirtualCluster({{"/GPU:1", device_properties}}));
  }
  Output SimpleConv2D(tensorflow::Scope* s, int input_size, int filter_size,
  