vredir.tests : wrong error message when setting ulimit under active descriptor

[MikeFultonDev]

When invoking the sequence:

unset v
exec {v}</dev/null
if (( v >= 10 )); then echo ok 1; else echo bad 1; fi
exec {v}<&-
ulimit -n 6

the output should be:

ok 1
failed to close file descriptor 11: bad file descriptor

but instead it is:

ok 1
bash: ulimit: open files: cannot modify limit: EDC5121I Invalid argument.