**Apache Airflow version**: 2.0.0b3

**Environment**: Python3.7-slim running on docker

**What happened**:

Error when running `airflow tasks test <dag> <task> <date>` there is an error with the task rescheduler, which should not happen as we are testing the tasks and not running via scheduler. 

**What you expected to happen**:

No error message should be displayed as the task is success and it is running on test mode

**How to reproduce it**:

just run the `airflow test <dag> <task> <date>` after a vanilla airflow installation using pip install.

**Anything else we need to know**:
this is the log
```
root@add8b3f038cf:/# airflow  tasks test docker_test d 2020-11-24 
[2020-11-24 08:13:00,796] {dagbag.py:440} INFO - Filling up the DagBag from /opt/airflow/dags/test
[2020-11-24 08:13:01,072] {taskinstance.py:827} INFO - Dependencies all met for <TaskInstance: docker_test.d 2020-11-24T00:00:00+00:00 [None]>
[2020-11-24 08:13:01,077] {taskinstance.py:827} INFO - Dependencies all met for <TaskInstance: docker_test.d 2020-11-24T00:00:00+00:00 [None]>
[2020-11-24 08:13:01,077] {taskinstance.py:1018} INFO - 
--------------------------------------------------------------------------------
[2020-11-24 08:13:01,077] {taskinstance.py:1019} INFO - Starting attempt 1 of 4
[2020-11-24 08:13:01,077] {taskinstance.py:1020} INFO - 
--------------------------------------------------------------------------------
[2020-11-24 08:13:01,078] {taskinstance.py:1039} INFO - Executing <Task(PythonOperator): d> on 2020-11-24T00:00:00+00:00
[2020-11-24 08:13:01,109] {taskinstance.py:1232} INFO - Exporting the following env vars:
AIRFLOW_CTX_DAG_EMAIL=adilson@zookal.com
AIRFLOW_CTX_DAG_OWNER=airflow
AIRFLOW_CTX_DAG_ID=docker_test
AIRFLOW_CTX_TASK_ID=d
AIRFLOW_CTX_EXECUTION_DATE=2020-11-24T00:00:00+00:00
d
[2020-11-24 08:13:01,110] {python.py:118} INFO - Done. Returned value was: None
[2020-11-24 08:13:01,115] {taskinstance.py:1143} INFO - Marking task as SUCCESS. dag_id=docker_test, task_id=d, execution_date=20201124T000000, start_date=20201124T081301, end_date=20201124T081301
Traceback (most recent call last):
  File "/usr/local/bin/airflow", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.7/site-packages/airflow/__main__.py", line 40, in main
    args.func(args)
  File "/usr/local/lib/python3.7/site-packages/airflow/cli/cli_parser.py", line 50, in command
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/airflow/utils/cli.py", line 86, in wrapper
    return f(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/airflow/cli/commands/task_command.py", line 379, in task_test
    ti.run(ignore_task_deps=True, ignore_ti_state=True, test_mode=True)
  File "/usr/local/lib/python3.7/site-packages/airflow/utils/session.py", line 63, in wrapper
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/airflow/models/taskinstance.py", line 1350, in run
    mark_success=mark_success, test_mode=test_mode, job_id=job_id, pool=pool, session=session
  File "/usr/local/lib/python3.7/site-packages/airflow/utils/session.py", line 59, in wrapper
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/airflow/models/taskinstance.py", line 1152, in _run_raw_task
    self._run_mini_scheduler_on_child_tasks(session)
  File "/usr/local/lib/python3.7/site-packages/airflow/utils/session.py", line 59, in wrapper
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/airflow/models/taskinstance.py", line 1165, in _run_mini_scheduler_on_child_tasks
    execution_date=self.execution_date,
  File "/usr/local/lib/python3.7/site-packages/sqlalchemy/orm/query.py", line 3473, in one
    raise orm_exc.NoResultFound("No row was found for one()")
sqlalchemy.orm.exc.NoResultFound: No row was found for one()
```


airflow/models/taskinstance.py
self.state = state
        self.hostname = ''
        self.init_on_load()
        
        
        self.raw = False
        
        self.test_mode = False
    @reconstructor
    def init_on_load(self):
        """Initialize the attributes that aren't stored in the DB"""
        self.test_mode = False  
    @property
    def try_number(self):
        """
        Return the try number that this task number will be when it is actually
        run.
        If the TaskInstance is currently running, this will match the column in the
        database, in all other cases this will be incremented.
        """
        
        
        if self.state in State.running:
            return self._try_number
        return self._try_number + 1
    @try_number.setter
    def try_number(self, value):
        self._try_number = value
    @property
    def prev_attempted_tries(self):