Fix persistence test

Author: MichaReiser

src/function/execute.rs

@@ -165,7 +165,6 @@ where
                 && old_memo.cycle_heads().contains(&database_key_index)
                 && !memo_iteration_count.is_panicked()
             {
-                // BUG, we need to pass in previous memo even for the first iteration.
                 last_provisional_memo = Some(old_memo);
                 iteration_count = memo_iteration_count;
             }

src/zalsa_local.rs

@@ -566,6 +566,7 @@ struct QueryRevisionsExtraInner {
 
     /// Stores for nested cycle heads whether they've converged in the last iteration.
     /// This value is always `false` for other queries.
+    #[cfg_attr(feature = "persistence", serde(skip))]
     cycle_converged: bool,
 }