Improve speed of dict literal with constant keys up to 30%.

The Python 3.5 change must not be applied to Python 3.6.

Reloading the warnings module duplicates filters in warnings.filters. Fixing
the issue is tricky. It was decided to simply remove the check from Python 3.5,
since the bug only impacts Python unit tests, not real applications.

The check is kept in Python 3.6 and newer.

Issue #28727: Regular expression patterns, _sre.SRE_Pattern objects created by
re.compile(), become comparable (only x==y and x!=y operators). This change
should fix the issue #18383: don't duplicate warning filters when the warnings
module is reloaded (thing usually only done in unit tests).

Patch by Xiang Zhang.

Patch by Xiang Zhang.

The fields ml_name and ml_doc are of type "const char *" rather of "char *".

The fields ml_name and ml_doc are of type "const char *" rather of "char *".

The fields ml_name and ml_doc are of type "const char *" rather of "char *".

rather of "char *".

Issue #28556: upstream improvements to docstrings and error messages by Ivan Levkivskyi (#331) (3.6->3.7)

Issue #28556: upstream improvements to docstrings and error messages by Ivan Levkivskyi (#331) (3.5->3.6)

It was deprecated in 3.4 and undocumented prior to that.

parameter now raises a DeprecationWarning.  It was deprecated in 3.4.
It was never documented prior to that.