Issue #12947: revert earlier workaround and use a monkey-patch to enable showing doctest directives only in the doctest docs.

Patch by Chris Jerdonek. Address Ezio's review comment.

Patch by Arne Babenhauserheide.

Patch by Arne Babenhauserheide.

Patch by Serhiy Storchaka.

#16112: platform.architecture does not correctly escape argument to /usr/bin/file. Fix original patch

#16112: platform.architecture does not correctly escape argument to /usr/bin/file. Use 'communicate()'

Thanks to Roger Serwy for patch.

Closes #16112: platform.architecture does not correctly escape argument to /usr/bin/file. Solve a 2.7 bootstrap issue

Issue #12947: Better workaround for the problem with doctest directives being stripped from code examples that are intended to illustrate those directives

See changeset 6ccb04c4cbae for the corresponding 3.3 change.

return a returncode of 0 when the child has already exited or cannot
be waited on.