Fixed #21840 -- Moved dunder methods from SimpleLazyObject to LazyObject.

This commit also added tests for LazyObject and refactored
the testsuite of SimpleLazyObject so that it can share
test cases with LazyObject.
Simplified implementation of collectstatic command.

Since d2e242d16c6dde6f4736086fb38057424bed3edb made isinstance()
calls work correctly on LazyObject, we can simplify the
implementation of is_local_storage added in
7e27885c6e7588471fd94a4def16b7081577bdfc.
Fix any sqlite field migration deleting all implicit m2m tables

Fixes #22281
Fixed #22283 -- Updated documentation referring to non-existent tuples.
Mentioned that ``dumpdata --natural`` is deprecated.
Made a test app label unique.
Fixed a regression from 2e5b82f6277227b69e9a6c5261a6deb14fff15dc
Fixed regression in file locking on some platforms.

Some platforms with os.name == 'posix' do not have the
fcntl module, e.g. AppEngine.

refs #19373.
Fixed migration so MySQL GIS test doesn't fail; refs #22001.

The test previously failed with the error:
(1170, "BLOB/TEXT column 'name' used in key specification without a key length")
Fixed #22253 -- Added django-i18n to the mailing lists docs.

Thanks bmispelon for the suggestion.
Replaced reference to ModelAdmin.get_formsets() (deprecated) with get_formsets_with_inlines().
Merge pull request #2221 from bmispelon/LazyObject-refactor

Fixed #21840 -- Moved dunder methods from SimpleLazyObject to LazyObject...
Fixed #22275: unique_together broken if ForeignKey split into new file.

Thanks to bak1an for the patch.
Mark model renaming as irreversible for now (#22248)
Removed a file accidentally added in 81f5408c7a16b8c79053950f05fe7a873506ca55.
Fixed a small collection of flake8 violations that had snuck in
Fixed #22163 -- Stopped ignoring unhandled kwargs in select_for_update.
Fixed minor syntax error in Queryset docs
Fixed #22255 -- Added support for specifying re flags in RegexValidator
Bumped version to reflect master is now pre-1.8.