sleep: customize one of the tests (tests/misc/sleep.sh)

[sylvestre]

No description provided.

[sylvestre]

Warning: Congrats! The gnu test tests/misc/sleep is no longer failing!

[tertsdiepraam]

I think we can still solve the exit code for sleep by changing this line:

let matches = uu_app().get_matches_from(args);

to

let matches = uu_app().try_get_matches_from(args)?;

That's probably better than changing the expected exit code. I do agree with the other customizations!