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**Description**

Related to the discussion here: https://github.com/apache/airflow/pull/8553#discussion_r416136954

Allow user to define expected terminal state. e.g. `JOB_STATE_CANCELLED` could be not treated as failure but expected terminal state.


<!-- A short description of your feature -->


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#
#
from __future__ import annotations
import copy
from copy import deepcopy
from unittest import mock
import pytest as pytest
import airflow
from airflow.providers.google.cloud.operators.dataflow import (
    CheckJobRunning,
    DataflowCreateJavaJobOperator,
    DataflowCreatePythonJobOperator,
    DataflowStartFlexTemplateOperator,
    DataflowStartSqlJobOperator,
    DataflowStopJobOperator,
    DataflowTemplatedJobStartOperator,
)
from airflow.version import version
TASK_ID = "test-dataflow-operator"
JOB_ID = "test-dataflow-pipeline-id"
JOB_NAME = "test-dataflow-pipeline-name"
TEMPLATE = "gs://dataflow-templates/wordcount/template_file"