message: Fixes is_initialized() behavior under custom devices.
  This is a "safe low blast radius" fix for a particular instance of a
  device placement shortcoming: an explicit device placement is
  never overridden by a custom device. This change fixes it for calls to
  is_initialized() while a complete solution is not available.
diff: @@ -800,6 +800,12 @@ class BaseResourceVariable(variables.VariableV1, core.Tensor):
  Returns:
  A `Tensor` of type `bool`.
  """
  + # TODO(b/169792703): The current device placement logic never overrides an
  + # explicit placement with a custom device, causing `v.is_initalized()` to
  + # fail under a non-custom device context if `v` is in a custom device. The
  + # explicit placement below makes this work, but should not be necessary once
  + # the logic is updated to handle cases like this.
  + with ops.device(self.device):
  return gen_resource_variable_ops.var_is_initialized_op(self.handle, name)
  def assign_sub(self, delta, use_locking=None, name=None, read_value=True):
  