Fix test filters todo

[waketzheng]

Description

Fixes TODO item in tests/test_filters.py

Motivation and Context

Django get result of: ['17', '17', '12']
But test_mysql_myisam get result of ['12', '17', '17']
So I add .order_by("id")

To reproduce Django result:

python3 -m venv venv
source venv/*/activate
pip install django
python -m django startproject haha
cd haha
python manage.py startapp foo
echo 'from django.db import models

class CharPkModel(models.Model):
    id = models.CharField(max_length=64, primary_key=True)

class CharFkRelatedModel(models.Model):
    model = models.ForeignKey(CharPkModel, related_name="children", on_delete=models.CASCADE)
' > foo/models.py
echo 'INSTALLED_APPS.append("foo")' >> haha/settings.py
python manage.py makemigrations
python manage.py migrate
python manage.py shell

from foo.models import *
objs=CharPkModel.objects.bulk_create([CharPkModel(id=i) for i in '17 12 2001'.split()])
CharFkRelatedModel.objects.bulk_create([CharFkRelatedModel(model=i) for i in (objs[0], objs[0], objs[1])])
CharPkModel.objects.filter(children__isnull=False).values_list('id', flat=True)

How Has This Been Tested?

make ci

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added the changelog accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.