*Note*: Before submitting this pull request, please review our [contributing
guidelines](https://docs.celeryq.dev/en/main/contributing.html).

## Description

<!-- Please describe your pull request.

NOTE: All patches should be made against main, not a maintenance branch like
3.1, 2.5, etc.  That is unless the bug is already fixed in main, but not in
that version series.

If it fixes a bug or resolves a feature request,
be sure to link to that issue via (Fixes #4412) for example.
-->
Avoid tests interference from each others.
integration test: cleanup worker after test case. *Note*: Before submitting this pull request, please review our [contributing
guidelines](https://docs.celeryq.dev/en/main/contributing.html).

## Description

<!-- Please describe your pull request.

NOTE: All patches should be made against main, not a maintenance branch like
3.1, 2.5, etc.  That is unless the bug is already fixed in main, but not in
that version series.

If it fixes a bug or resolves a feature request,
be sure to link to that issue via (Fixes #4412) for example.
-->
Avoid tests interference from each others.
# Generated by Django 2.2.1 on 2019-05-24 21:37

from django.db import migrations, models


class Migration(migrations.Migration):

    initial = True

    dependencies = [
    ]

    operations = [
        migrations.CreateModel(
            name='Widget',
            fields=[
                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                ('name', models.CharField(max_length=140)),
            ],
        ),
    ]

# Generated by Django 2.2.1 on 2019-05-24 21:37

from django.db import migrations, models


class Migration(migrations.Migration):

    initial = True

    dependencies = [
    ]

    operations = [
        migrations.CreateModel(
            name='Widget',
            fields=[
                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                ('name', models.CharField(max_length=140)),
            ],
        ),
    ]
