Function invariant_suite_paths 

fn invariant_suite_paths(
    corpus_config: &mut FuzzCorpusConfig,
    persist_dir: PathBuf,
    contract_name: &str,
    isolated_campaign: Option<&str>,
    execution_profile: &str,
    execution_pass: &str,
) -> PathBuf

Sets the invariant corpus directory and returns the contract-level failure directory.