Added main function to the two keras resent benchmarks (#6546)

* Added main function to the two keras resent benchmarks

* remove asserts

official/resnet/keras/keras_cifar_benchmark.py

@@ -233,3 +233,7 @@ class Resnet56KerasBenchmarkReal(Resnet56KerasBenchmarkBase):
 
     super(Resnet56KerasBenchmarkReal, self).__init__(
         output_dir=output_dir, default_flags=default_flags)
+
+
+if __name__ == '__main__':
+  tf.test.main()

official/resnet/keras/keras_imagenet_benchmark.py

@@ -666,3 +666,7 @@ class TrivialKerasBenchmarkReal(keras_benchmark.KerasBenchmark):
         stats,
         total_batch_size=FLAGS.batch_size,
         log_steps=FLAGS.log_steps)
+
+
+if __name__ == '__main__':
+  tf.test.main()