Simplify test helper

src/engine/snapshot/mod.rs

@@ -122,9 +122,7 @@ impl EngineSnapshot {
                 _ => None,
             })
     }
-}
 
-impl EngineSnapshot {
     pub(crate) fn from_index(index: BTreeMap<IndexKey, DataValue>) -> Self {
         let mut snapshot = EngineSnapshot { index, ..Default::default() };
         snapshot.rebuild_regex_caches();