class_docstr: Single vgg layer in NCHW unit tests in TF-TRT.
code: def setUp(self):
      super().setUp()
      os.environ[
          "TF_TRT_ALLOW_ENGINE_NATIVE_SEGMENT_EXECUTION"
      ] = "True"
  
file_path: tensorflow-upstream/tensorflow/python/compiler/tensorrt/test/vgg_block_nchw_test.py
imports: import os
  import numpy
  from tensorflow.python.compiler.tensorrt.test import tf_trt_integration_test_base
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import nn
  from tensorflow.python.ops import nn_impl
  from tensorflow.python.ops import nn_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 4 for calling the VGGBlockNCHWTest obj's underlying member method code with example usage: obj.setUp() without return types