Fixed #22814 -- Allowed ISO-8601 [+-]hh timezone format in parse_datetime

Thanks Josh Parris.

An ImproperlyConfigured exception will be raised they mismatch.

Fixes a regression introduced in 5f24cf97. Refs #22635.
Thanks A.J. May for spotting the regression.

This fixes a regression on Windows introduced by b7de5f5d.

Thanks Tim Graham for the report and review.

The data migration failed on Oracle, killing the entire test suite.

Thanks timo for reporting the Oracle breakage,
and andrewgodwin for suggesting the solution.

Thanks Rahul Priyadarshi.

And moved `tablespaces` option tests to it.
The new folder can be used to test models/options, like the new option
added in refs #22778.

When using tab-completion it's easy to accidentally run a test with
a trailing slash, which causes INSTALLED_APPS to be set incorrectly.
Normalize the test labels to avoid this common error.

Thanks MattBlack for the suggestion.

Fixed #21430 -- Added a RuntimeWarning when unpickling Models and QuerySets from a different Django version.

Thanks FunkyBob for the suggestion, prasoon2211 for the initial patch,
and akaariai, loic, and charettes for helping in shaping the patch.

This patch is two-fold; first it ensure that Django does close everything in
request.FILES at the end of the request and secondly the storage system should
no longer close any files during save, it's up to the caller to handle that --
or let Django close the files at the end of the request.

Thanks Odd_Bloke for the report.

Moved logic to syncdb command for backwards compatibility.

Credits for the initial patch go to ejucovy;
big thanks to Tim Graham for the review.

It prevented the GZipMiddleware from compressing some data types even on
more recent version of IE where the corresponding bug was fixed.

Thanks Aaron Cannon for the report and Tim Graham for the review.

This is achieved by inserting a fake entry in connection.queries when
not releasing a savepoint (since Oracle doesn't support that operation.)

Also removed the can_release_savepoints feature that was recently added,
but is superseded by this solution.

Turned it from a tri-valued boolean into a regular boolean.

Since `serialize` was backported to 1.7, it should appear before `keepdb`.

Fixes #19905 again.

Refs #19973.