Adjust the test considering the POSIX-compliant behavior of the
NuttX's FIFO (mkfifo), which should block `open` for read-only
and write-only. This test's result is expected to be the same with
any other POSIX-compliant system.
This commit also:
* Fix redirect test;
* Use pthread instead `task_create` to be able to run this test
on POSIX-compliant systems;
* General fixes regarding formatting and error messages;
0a9b983e90