message: Fix TPU nightly build script.
  We can't pass a single string containing all the arguments, since it'll be taken as a single argument instead. Storing as an array allows us to safely expand.
diff: @@ -35,22 +35,24 @@ export TF2_BEHAVIOR=1
  yes "" | "$PYTHON_BIN_PATH" configure.py
  -tag_filters="tpu,requires-tpu,-no_tpu,-notpu,-no_oss,-no_oss_py37"
  +tag_filters="tpu,-no_tpu,-notpu,-no_oss,-no_oss_py37"
  -bazel_args="--config=opt \
  +bazel_args=(
  + --config=opt \
  --crosstool_top=//third_party/toolchains/preconfig/ubuntu16.04/gcc7_manylinux2010-nvcc-cuda10.1:toolchain \
  --linkopt=-lrt \
  - --action_env=TF2_BEHAVIOR=${TF2_BEHAVIOR} \
  + --action_env=TF2_BEHAVIOR="${TF2_BEHAVIOR}" \
  --noincompatible_strict_action_env \
  - --build_tag_filters=${tag_filters} \
  - --test_tag_filters=${tag_filters} \
  + --build_tag_filters="${tag_filters}" \
  + --test_tag_filters="${tag_filters}" \
  --test_output=errors --verbose_failures=true --keep_going \
  - --test_arg=--tpu=${TPU_NAME} \
  - --test_arg=--zone=${TPU_ZONE} \
  + --test_arg=--tpu="${TPU_NAME}" \
  + --test_arg=--zone="${TPU_ZONE}" \
  --test_arg=--test_dir_base=gs://kokoro-tpu-testing/tempdir/ \
  --local_test_jobs=1 \
  - -- //tensorflow/... -//tensorflow/compiler/... -//tensorflow/lite/..."
  + -- //tensorflow/... -//tensorflow/compiler/... -//tensorflow/lite/...
  +)
  -bazel build "${bazel_args}"
  +bazel build "${bazel_args[@]}"
  ctpu_up -s v2-8 -p tensorflow-testing-tpu
  -bazel test "${bazel_args}"
  +bazel test "${bazel_args[@]}"
  