Patch by Matt Morrison.

Several test cases in distutils use PyPIRCCommandTestCase as
their base class and as a result of that the following tests
were ran more than once:

* test_server_registration
* test_server_empty_registration
* test_config_interpolation

This commit moves the infrastructure used by other tests
into a new BasePyPIRCCommandTestCase class.

Patch by Yoni Lavi

Rest of patch that should not be cherry picked into 3.5.2 final.

I noticed that there is no test for this feature while doing
triaging work on pypa/pypi-legacy.

represented as a compination of known flags.

Patch contributed Марк Коренберг.

an iterable of integers. Now only strings and byte-like objects are accepted.

Issue #27048: Prevents distutils failing on Windows when environment variables contain non-ASCII characters

Issue #27278. It should fix a conversion warning.

In practice, the Linux kernel doesn't return more than 32 MB per call to the
getrandom() syscall.

Patch by John Hagen.

by Jelle Zijlstra.

managed by a contextlib.ExitStack() and one of the exit stack
generators catches and raises it in a chain, do not re-raise the
original exception when exiting, let the new chained one through.
This avoids the PEP 479 bug described in issue25782.

Casting Py_ssize_t to Py_ssize_t is useless.

Issue #27278: Fix os.urandom() implementation using getrandom() on Linux.
Truncate size to INT_MAX and loop until we collected enough random bytes,
instead of casting a directly Py_ssize_t to int.

They are not used as base classes by another tests so they
can safely be removed.

sqlite3.OptimizedUnicode is an alias for str in Python 3 and
its behavior is already tested in CheckOptimizedUnicode in
Lib/sqlite3/test/factory.py.

sqlite3.OptimizedUnicode was undocumented in 0fc10a33eb4c and
probably added back with the result of a bad merge.