Fix IO redirection in Zephyr

[casaroli]

Description

Currently, WAMR Zephyr integration does not work if we pass the file descriptors for stdio. It should work just as it does in linux

Work

1. Revert commit 697ce1c
2. Fix the system test (the fix is most probably in WAMR)
3. Bonus: add more tests

Acceptance criteria

• 697ce1c is reverted
• Zephyr system tests are working