Fixes #1376. Broken co19_2 test fixed (#1377)

Authored by @sgrekhov.

Author: sgrekhov

Language/Statements/For/Asynchronous_For_in/execution_t04.dart

@@ -68,9 +68,11 @@ Future test2() async {
 
 // try an already closed single subscription stream
 Future test3() async {
-  // make a stream that is closed
-  Stream stream = new Stream.fromIterable([1, 2]);
-  await for (var x in stream) {
+  Stream<int> generator() async* {
+    yield 42;
+  }
+  Stream stream = generator();
+  await for (var i in stream) {
   }
   var processedValues = [];
   try {
@@ -87,7 +89,6 @@ Future test3() async {
   Expect.isTrue(processedValues.isEmpty);
 }
 
-
 main() {
   asyncStart();
   Future.wait([test1(), test2(), test3()]).then((v) => asyncEnd());