[issue3643] Add more checks to testcapi

[Georg Brandl]

Georg Brandl <georg at python.org> added the comment:

Still, _testcapi is built even for non-debug builds, so it is a
gratuitous way for bad code to crash or internally invalidate a Python
interpreter, so this should be treated like a bugfix.

----------
nosy: +georg.brandl
priority: normal -> high

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue3643>
_______________________________________