Occasional wait test fail

[viraptor]

Very occasionally when testing, I run into this test failure. Seems timing / race related.

test test_unistd::test_execve ... FAILED
test test_unistd::test_wait ... FAILED

failures:

---- test_unistd::test_execve stdout ----
        thread 'test_unistd::test_execve' panicked at 'called `Result::unwrap()` on an `Err` value: Sys(ECHILD)', ../src/libcore/result.rs:741

---- test_unistd::test_wait stdout ----
        thread 'test_unistd::test_wait' panicked at 'assertion failed: `(left == right)` (left: `Ok(Exited(2837, 0))`, right: `Ok(Exited(2843, 0))`)', test/test_unistd.rs:41


failures:
    test_unistd::test_execve
    test_unistd::test_wait

[kamalmarhubi]

Closing this as a dupe of #251

Thanks for the report though! I'm glad to know it wasn't just me...