message: Make variable_ops_test optonly
  variable_ops_test sometimes times out in fastbuild mode.  So mark it as optonly.
  Running this test with `bazel test -c opt` passes all 1000 of 1000 reruns.
  Running it with just `bazel test` fails 5 out of 300 reruns.
diff: @@ -639,6 +639,7 @@ tf_xla_py_test(
  name = "variable_ops_test",
  size = "small",
  srcs = ["variable_ops_test.py"],
  + tags = ["optonly"],
  deps = [
  ":xla_test",
  "//tensorflow/python:array_ops",
  