additional performance improvement for chunks with single source type

lib/ChunkGraph.js

@@ -78,6 +78,13 @@ const modulesBySourceType = set => {
 			innerSet.add(module);
 		}
 	}
+	for (const [key, innerSet] of map) {
+		// When all modules have the source type, we reuse the original SortableSet
+		// to benefit from the shared cache (especially for sorting)
+		if (innerSet.size === set.size) {
+			map.set(key, set);
+		}
+	}
 	return map;
 };