starknet_os: make sure the virtual output iterator is fully consumed

[Yoni-Starkware]

No description provided.

[reviewable-StarkWare]

This change is 

[AvivYossef-starkware]

@AvivYossef-starkware reviewed 2 files and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @noaov1).

---

crates/starknet_os/src/io/virtual_os_output.rs line 41 at r1 (raw file):

        if iter.next().is_some() {
            return Err(OsOutputError::OutputNotExhausted);
        }

Suggestion:

        // Verify that we have consumed all output.
        if iter.next().is_some() {
            return Err(OsOutputError::OutputNotExhausted);
        }

[Yoni-Starkware]

@Yoni-Starkware reviewed 2 files and all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @noaov1).