Changed Oracle test-user creation to grant privileges instead of roles

because the roles (specifically RESOURCE) are deprecated.
Also added optional support for creating views in tests, and made an
introspection test fail (rather than skip)  if a view cannot be created
due to lacking privileges.

Refs #18782

Thanks Tim Graham for review, and Josh Smeaton
Removed numbering from the models.py header of some test packages.

This is a reliqua from the early days of the modeltests/regressiontests era.
Fixed #23539 -- Added get_extra(), get_max_num(), and get_min_num() hooks to GenericInlineModelAdmin.
Fixed flake8 warnings.
Fixed #23426 -- Don't require double percent sign in RunSQL without parameters
Added SuspiciousOperation to list of caught exceptions in testing docs.
Corrected --noinput docs for makemigrations; refs #23407.
Fixed #23473 -- Documented that @deconstructible classes need __eq__.
Fixed #22959 -- Documented that class-based validators need to be deconstructible.
Fixed #23421 -- Corrected TEST SERIALIZE setting.

Thanks gkoller for the report.
Revert "Fixed #23474 -- Prevented migrating backwards from unapplying the wrong migrations."

This reverts commit abcf28a07695a45cb5fb15b81bffc97bea5e0be3.