message: Add a simple build_test to core/platform:platform_port to prevent regressions.
diff: # The libraries in this package are not allowed to have ANY dependencies
  # to any TensorFlow code outside this package.
  +load("@bazel_skylib//rules:build_test.bzl", "build_test")
  load(
  "//tensorflow/core/platform:default/build_config.bzl",
  "tf_additional_lib_hdrs",
  @@ -332,6 +333,11 @@ cc_library(
  deps = tf_platform_helper_deps("platform_port_impl"),
  )
  +build_test(
  + name = "platform_port_build_test",
  + targets = [":platform_port"],
  +)
  +
  cc_library(
  name = "platform_strings",
  srcs = [
  