Add Iterable.fold (and Stream.fold) which replace `reduce`.

tests/corelib/list_map_test.dart

Index: tests/corelib/list_map_test.dart
diff --git a/tests/corelib/list_map_test.dart b/tests/corelib/list_map_test.dart
index ca30d4a0e4887e2f589f3e84c538435d4b41e8c0..31d3439bb2a4de9fb9f5e89b12b32ba6fbbe2f9f 100644
--- a/tests/corelib/list_map_test.dart
+++ b/tests/corelib/list_map_test.dart
@@ -116,6 +116,7 @@ void testOperations() {
     testOp((i) => i.max(), "max");
     testOp((i) => i.min(), "min");
     testOp((i) => i.reduce(0, (a, b) => a + b), "reduce-sum");

[Lasse Reichstein Nielsen, 2013/04/04 08:35:18]

Remove the reduce line. It's deprecated.

[floitsch, 2013/04/05 16:10:03]

I prefer keeping it. When I change the reduce to the new behavior I will get an
error during tests and make sure to add a new test-case.

+    testOp((i) => i.fold(0, (a, b) => a + b), "fold-sum");
     testOp((i) => i.join("-"), "join-");
     testOp((i) => i.join(""), "join");
     testOp((i) => i.join(), "join-null");