Revert "Allowed running GIS form tests that don't require spatial database"

This reverts commit 07fe0bf3f4a49a734f83f5ea30130449dacf9660.
This was not working properly on system without geos library
installed.
Fixed #21539 -- Added example of modelformset_factory's form argument
Added internal link to i18n documentation.
Typo in 1.7 release notes
Fix docs typo
Fixed #21621 -- Removed kqueue autoreloader.
Merge pull request #2079 from brutasse/master

Typo in 1.7 release notes
Fixed #21619 -- Made SingleObjectMixin.get_object catch a more precise exception.

Thanks to Keryn Knight for the report.
Added some internal links to render_to_string documentation.
Removed unnecessary call to force_text in utils.html.clean_html.

Refs #21574
Removed unnecessary function-level import.
Fixed #21564 -- Use local request object when possible in generic views.

Thanks to trac user adepue for the report and original patch.
Fixed #17413 -- Serialization of form errors along with all metadata.
Removed duplicated `TimeField` in __all__.
Moved django.db.models.loading to django.apps.cache.

This commit doesn't contain any code changes; it's purely a refactoring.
Removed BaseAppCache.app_store.

It was only storing redundant information. This is part of the effort to
allow applications without a models module.
Removed ModelDict.

Its only difference with OrderedDict is that it didn't deepcopy its
keys. However it wasn't used anywhere with models modules as keys, only
as values. So this commit doesn't result in any change in functionality.
Removed module-level functions for the app cache.

Since the original ones in django.db.models.loading were kept only for
backwards compatibility, there's no need to recreate them. However, many
internals of Django still relied on them.

They were also imported in django.db.models. They never appear in the
documentation, except a quick mention of get_models and get_app in the
1.2 release notes to document an edge case in GIS. I don't think that
makes them a public API.

This commit doesn't change the overall amount of global state but
clarifies that it's tied to the app_cache object instead of hiding it
behind half a dozen functions.
Stored AppConfig objects instead of models modules in the app cache.

This is a step towards allowing applications without a models module.
Removed unused attribute app_errors of the app cache.

get_app_errors() always returned an empty dictionary; this behavior is
preserved in django.db.models.loading until that module is deprecated.