Bug report

Bug description:

#111638 broke WASI builds due to assuming multiprocessing was always available.

Failure can be seen at https://buildbot.python.org/all/#/builders/1046/builds/3844 .

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-113692: skip a test if multiprocessing isn't available. #113704
• [3.12] gh-113692: skip a test if multiprocessing isn't available. (GH-113704) #113844