bpo-39573: Use Py_TYPE() macro in Objects directory

[vstinner]

Replace direct access to PyObject.ob_type with Py_TYPE().

https://bugs.python.org/issue39573

[codecov]

Codecov Report

Merging #18392 into master will decrease coverage by 0.05%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #18392      +/-   ##
==========================================
- Coverage   83.24%   83.19%   -0.06%     
==========================================
  Files        1570     1570              
  Lines      414397   414397              
  Branches    44429    44429              
==========================================
- Hits       344979   344755     -224     
- Misses      59767    59995     +228     
+ Partials     9651     9647       -4     

Impacted Files	Coverage Δ
Lib/distutils/tests/test_bdist_rpm.py	30.00% <0.00%> (-65.00%)	⬇️
Lib/distutils/command/bdist_rpm.py	7.63% <0.00%> (-56.88%)	⬇️
Lib/test/test_urllib2net.py	76.92% <0.00%> (-13.85%)	⬇️
Lib/test/test_smtpnet.py	78.57% <0.00%> (-7.15%)	⬇️
Lib/ftplib.py	63.85% <0.00%> (-6.06%)	⬇️
Lib/test/test_ftplib.py	87.11% <0.00%> (-4.72%)	⬇️
Tools/scripts/db2pickle.py	17.82% <0.00%> (-3.97%)	⬇️
Tools/scripts/pickle2db.py	16.98% <0.00%> (-3.78%)	⬇️
Lib/test/test_socket.py	71.94% <0.00%> (-3.77%)	⬇️
Lib/test/test_asyncio/test_base_events.py	91.84% <0.00%> (-3.30%)	⬇️
... and 51 more

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