Increases //tensorflow_serving/core:basic_manager_test test size
Increases //tensorflow_serving/core:basic_manager_test test size

This test is timeout flaky on ci.bazel.io, see:
  http://ci.bazel.io/job/TensorFlow_Serving/81/BAZEL_VERSION=HEAD,PLATFORM_NAME=linux-x86_64/console
  http://ci.bazel.io/job/TensorFlow_Serving/84/BAZEL_VERSION=HEAD,PLATFORM_NAME=linux-x86_64/console

sreddybr3/serving,penguin138/serving,tensorflow/serving,kchodorow/serving,tensorflow/serving,addappio/serving,avloss/serving,avloss/serving,kchodorow/serving,jharmsen/serving,tensorflow/serving,jharmsen/serving,sreddybr3/serving,penguin138/serving,addappio/serving,jharmsen/serving,avloss/serving,tensorflow/serving,kchodorow/serving,addappio/serving,avloss/serving,penguin138/serving,sreddybr3/serving,sreddybr3/serving,penguin138/serving,addappio/serving