Fix possibly missed optimization.

[ilyalesokhin-starkware]

No description provided.

[reviewable-StarkWare]

This change is 

[orizi]

Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion (waiting on @ilyalesokhin-starkware and @liorgold2)

---

crates/cairo-lang-lowering/src/optimizations/match_optimizer.rs line 330 at r1 (raw file):

            candidate.match_variable = var_usage.var_id;
            handled_remmapings = 1;
        };

Suggestion:

        if remapping.is_empty() { <----- Doesn't this already do that?
            // Do nothing. Keep the candidate if exists.
            return;
        }

        info.demand.apply_remapping(
            &mut EmptyDemandReporter {},
            remapping.iter().map(|(dst, src)| (dst, (&src.var_id, ()))),
        );

        let Some(ref mut candidate) = &mut info.candidate else {
            return;
        };

        let orig_match_variable = candidate.match_variable;
        let mut handled_remmapings = 0;
        if let Some(var_usage) = remapping.get(&candidate.match_variable) {
            candidate.match_variable = var_usage.var_id;
            handled_remmapings = 1;
        };