Add tests for std::pipe

[RalfJung]

std now has a pipe module. We should add a test in Miri to see which OS APIs are required for this.

• On Unix, AFAIK this uses pipe2. Miri has basic support for that but does not support blocking, so properly supporting std::pipe is blocked on the socketpair part of Implement blocking support for eventfd and socketpair #3665.
• On Windows, for now it's okay to ignore the test like we do for many other OS APIs. But of course if someone wants to implement this, they can give it a go. :) This will require someone reasonably familiar with Windows APIs since the Miri team does not have the expertise for that.