Formatters run on `TemplateCommand` make `admin_scripts` tests brittle

[Natalia Bidart]

Some admin_scripts tests, such as those for startproject, assert literal file contents generated from templates. Because TemplateCommand runs formatters before exiting (run_formatters(...)), the output can differ depending on environment details such as temporary directory path length or whether black is installed.

For example, when black reformats long lines during parallel test runs, strings in the generated manage.py file are wrapped in parentheses, causing assertion failures.

Tests should not depend on the exact output of formatters. Mocking or disabling them during test runs would make the suite more stable.

[Natalia Bidart]

There are other tests failures that need to be logged at.

[Jacob Walls]

I expect some more discussion about the merit of the approach, but I pushed some edits that should handle those failures.