samples/net/sockets/socketpair does not run as expected

[rymaj]

Describe the bug
I tried to run samples/net/socket/socketpair, and got the folllowing issue first,

*** Booting Zephyr OS build zephyr-v3.2.0-585-ge80a0c35e666  ***
Alpha: socketpair: 1 <=> 0
Bravo: socketpair: 3 <=> 2
socketpair failed: 23
Alpha closed fd 0
Bravo closed fd 2

Then I figure out I need to increase the default CONFIG_POSIX_MAX_FDS from 4 to 8 for 3 socket pairs (should this change be covered in socketpair/prj.conf ?)

Even I add this setting, I saw this issue, seems the poll mechanism was broken?

*** Booting Zephyr OS build zephyr-v3.2.0-585-ge80a0c35e666  ***
Alpha: socketpair: 1 <=> 0
Bravo: socketpair: 3 <=> 2
Charlie: socketpair: 5 <=> 4
fd: 1: read 5 bytes
fd: 1: read 5 bytes
fd: 1: read 5 bytes
fd: 1: read 0 bytes
fd: 1: read 0 bytes
fd: 1: read 0 bytes
<keep looping>
fd: 1: read 0 bytes
fd: 1: read 0 bytes
fd: 1: read 0 bytes
fd: 1: read 0 bytes

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• Is this a regression? If yes, have you been able to "git bisect" it to a
  specific commit?
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To Reproduce
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1. mkdir build; cd build
2. cmake -DBOARD=board_xyz
3. make
4. See error

Expected behavior
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Impact
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[cfriedt]

@rymaj - can you please update the upstream commit in the bug report?

[cfriedt]

It's kind of a PITA to have to jump through all of the hoops and enable a network device just to use socketpair, which really shouldn't require any kind of network interface at all.

Even just trying to run the sample application, I get an error:

west build -p auto -b mps2_an385 -t run samples/net/sockets/socketpair
...
qemu-system-arm: -serial unix:/tmp/slip.sock: Failed to connect to '/tmp/slip.sock': No such file or directory
qemu-system-arm: -serial unix:/tmp/slip.sock: could not connect serial device to character backend 'unix:/tmp/slip.sock'
FAILED: zephyr/CMakeFiles/run_qemu /Users/cfriedt/workspace/zephyrproject/zephyr/build/zephyr/CMakeFiles/run_qemu 
cd /Users/cfriedt/workspace/zephyrproject/zephyr/build && /opt/homebrew/bin/qemu-system-arm -cpu cortex-m3 -machine mps2-an385 -nographic -vgf
ninja: build stopped: subcommand failed.
FATAL ERROR: command exited with status 1: /opt/homebrew/bin/cmake --build /Users/cfriedt/workspace/zephyrproject/zephyr/build --target run

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