test_socket: ThreadedVSOCKSocketStreamTest.testStream errors on a VSOCK guest whose transport reports ENODEV

[rudi193-cmd]

Bug report

$ ./python -m test test_socket -m ThreadedVSOCKSocketStreamTest -v
testStream (test.test_socket.ThreadedVSOCKSocketStreamTest.testStream) ... ERROR
TimeoutError: timed out
OSError: [Errno 19] No such device
Result: FAILURE

Reproduced on `main` at `cfd6cf7`, and on 3.14.8 and 3.15.0rc3. `HAVE_SOCKET_VSOCK` only checks that the local CID can be read from `/dev/vsock`, not that a connection can be made.


### CPython versions tested on:

CPython main branch

### Operating systems tested on:

Linux