Fixes: #5113

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### Description
Add py3.8 and py3.9 tokens to setup.py

### Checklist
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This pull request is:

- [ ] A documentation / typographical error fix
	- Good to go, no issue or tests are needed
- [x] A short code fix
	- please include the issue number, and create an issue if none exists, which
	  must include a complete example of the issue.  one line code fixes without an
	  issue and demonstration will not be accepted.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.   one line code fixes without tests will not be accepted.
- [ ] A new feature implementation
	- please include the issue number, and create an issue if none exists, which must
	  include a complete example of how the feature would look.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.

**Have a nice day!**

Closes: #5115
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5115
Pull-request-sha: 5ae662f1ec0d89a16a03fe60d6f12712d0d21398

Change-Id: I1313df9bd117b1356c1d06d588e8e04a07ba4e39

The C extensions have been broken since cc718cccc0bf8a01abdf4068c
however CI did not find this, because the build degraded to
non-C extensions without failing.   Ensure that if cext is set,
there is no fallback to non-cext build if the C extension build
fails.

Repair C related issues introduced in cc718cccc0bf8a01abdf4068c.

As C extensions have been silently failing on 2.7 for some commits,
the callcounts also needed to be adjusted for recent performance-related
changes.  That in turn required a fix to the profiling decorator
to use signature rewriting in order to support py.test's
fixture mechanism under Python 2, usage introduced under profiling
in 89bf6d80a9.

Fixes: #5076
Change-Id: Id968f10c85d6bf489298b1c318a1f869ad3e7d80

Added a workaround for a setuptools-related failure that has been observed
as occurring on Windows installations, where setuptools is not correctly
reporting a build error when the MSVC build dependencies are not installed
and therefore not allowing graceful degradation into non C extensions
builds.

Setuptools issue https://github.com/pypa/setuptools/issues/1902

Fixes: #4967
Change-Id: I5e21e7e78cb6d927b18afce64cacf8643b98354e

general README.unittest.rst edits

Fixes: #4789
Fixes: #4900
Change-Id: Ifddd3bfd1e6a4d24d3b0a3e1702e04e66a42a4dd

While we have the OSI classifier for "MIT License", it looks
like for the "license" field, this is normally just the word
"MIT" and not "MIT License".   While the pypa docs suggest we
only need it as the OSI classifier, keep it also in "license"
in order to appease common tooling.

Change-Id: Ife51bbc74d6c1b8ab9a736024818fbba35316e17

Change-Id: I379b3d9e59ff8cda17c2d738fde794249f105510

Applied on top of a pure run of black -l 79 in
I7eda77fed3d8e73df84b3651fd6cfcfe858d4dc9,  this set of changes
resolves all remaining flake8 conditions for those codes
we have enabled in setup.cfg.

Included are resolutions for all remaining flake8 issues
including shadowed builtins, long lines, import order, unused
imports, duplicate imports, and docstring issues.

Change-Id: I4f72d3ba1380dd601610ff80b8fb06a2aff8b0fe

This is a straight reformat run using black as is, with no edits
applied at all.

The black run will format code consistently, however in
some cases that are prevalent in SQLAlchemy code it produces
too-long lines.   The too-long lines will be resolved in the
following commit that will resolve all remaining flake8 issues
including shadowed builtins, long lines, import order, unused
imports, duplicate imports, and docstring issues.

Change-Id: I7eda77fed3d8e73df84b3651fd6cfcfe858d4dc9

Fixes to the test suite, a few errant imports, and setup.py:

- mysql and postgresql have unused 'json' imports; remove
- postgresql is exporting the 'json' symbol, remove
- make sure setup.py can find __version__ using " or '
- retry logic in provision create database for postgresql fixed
- refactor test_magazine to use cls.tables rather than globals
- remove unused class in test_scoping
- add a comment to test_deprecations that this test suite itself
  is deprecated
- don't use mapper() and orm_mapper() in test_unitofwork, just
  use mapper()
- remove dupe test_scalar_set_None test in test_attributes
- Python 2.7 and above includes unittest.SkipTest, remove pre-2.7
  fallback
- use imported SkipTest in profiling
- declarative test_reflection tests with "reflectable_autoincrement"
  already don't run on oracle or firebird; remove conditional logic
  for these, which also removes an "id" symbol
- clean up test in test_functions, remove print statement
- remove dupe test_literal_processor_coercion_native_int_out_of_range
  in test/sql/test_types.py
- fix psycopg2_hstore ref

Change-Id: I7b3444f8546aac82be81cd1e7b6d8b2ad6834fe6

Change-Id: I35ecd78b92ea420ef7909de65f82e005b92bf986