gh-116622: Redirect stdout and stderr to system log when embedded in an Android app

[mhsmith]

When embedded in an app on current versions of Android, there's no easy way to monitor the process's stdout and stderr. So, as specified in PEP 738, this PR redirects them to the system log, which can be viewed using the developer tools.

• Issue: Add support for Android as a target platform #116622

[mhsmith]

@serhiy-storchaka: This PR is connected to the io module, which I see you've been working on recently. Are you able to review it?

[encukou]

Thank you!
This looks good to me, modulo a few small nitpicks. I'll let @serhiy-storchaka resolve the conversations he started.

[serhiy-storchaka]

Thank you for addressing my comments. LGTM in general. I left several minor suggestions, but they are not mandatory, you can implement or reject them on case by case base.

In any case I'm going to merge this PR after your answer.

[encukou]

Using the tooling and instructions in #117878, I've confirmed that this works for the test suite:

[vstinner]

Merged. Let's see how it goes. It can be adjusted later if needed.

Nice change @mhsmith.