Thanks Pavel Pokrovskiy for the report and Tim Graham for the review.

Thanks revimi for the initial patch.

Thanks Mariusz Felisiak for review and MySQL advice.

Instead of a 404, return a redirect to admin index page with a message
indicating that the requested object does not exist. This avoids the
admin returning 404 from "Recent Actions" links for deleted objects.

Thanks Tim Graham for the review.

On a SyntaxError, made runserver exit with a stacktrace when using
contrib.staticfiles's runserver options such as --nostatic.

Removed unused DatabaseFeatures.driver_supports_timedeltas workaround.

Removed obsolete workarounds from 1aa48898
and dcf3be7a.

Executing a DDL statement during a transaction on backends that don't support
it silently commits, leaving atomic() in an incoherent state.

While schema_editor.execute() could technically be used to execute DML
statements such usage should be uncommon as these are usually performed through
the ORM. In other cases schema_editor.connection.execute() can be used to
circumvent this check.

Thanks Adam and Tim for the review.