Thanks to Henrik Levkowetz and olau for their reports and initial patches.

Cleanup/pep8 tests

Fixed flake8 E251 violations

Signed-off-by: Jason Myers <jason@jasonamyers.com>

Depending on the order of the tests beeing run, 10 can be a valid pk,
0 can never be a valid pk and as such we will get the wanted ValidationError.

Refs #21302

model_to_dict() (used when rendering forms) queries the database
to get the list of primary keys for ManyToMany fields. This is
unnecessary if the field queryset has been prefetched, all the
keys are already in memory and can be obtained with a simple
iteration.

Fixed failing test around DST change.

Signed-off-by: Jason Myers <jason@jasonamyers.com>

Signed-off-by: Jason Myers <jason@jasonamyers.com>

Signed-off-by: Jason Myers <jason@jasonamyers.com>

Signed-off-by: Jason Myers <jason@jasonamyers.com>

Correct flake8 E302 violations

The timezone arithmetic done in JS can be off by one hour around DST
change. We work around this issue by adding one extra hour to the test
error margin when we detect a DST change is near.

Refs #20663.

Fixed flake8 E241

Correct flake8 violation E261

Django should be capitalized in text