This fixes a regression caused by revision 73afda5a4e4c. Also reverts the
decimal test workaround added in revision 5f3dd0a2b1ab.

Remove test_without_exception(). According to revision ecaafc32c500, this was
added in Python 2 so that print_exc() would output “None” when called with no
exception set. However print_exc() never worked like this in Python 3, and
the use case is not documented.

Restore TracebackCases class name (instead of SyntaxTracebackCases), because
the class also tests other exceptions.

Issue #28233: Fix a memory leak if the format string contains a non-ASCII
character, destroy the unicode writer.

Issue #28176: Increase timeout from 10 seconds to 60 seconds.

Issue #27955: Fallback on reading /dev/urandom device when the getrandom()
syscall fails with EPERM, for example when blocked by SECCOMP.

Issue #27955: modify py_getrnadom() and dev_urandom()

* Add comments from Python 3.7
* PEP 7 style: add {...}

 (Patch by Xiang Zhang)

I forgot there two variations of os.stat() in Python 3.5.

Patch by Eryk Sun.

Also update the classmethod and staticmethod doc strings and comments to
match the RST documentation.

Issue #25270: Prevent codecs.escape_encode() from raising SystemError when an empty bytestring is passed

Patch by Gergely Imreh and Markus Holtermann.

Patch by Mark Williams.

Patch by INADA Naoki.

Patch by iceboy.

Patch by Seth Michael Larson.

Patch by Kevin Conway.