Re-apply "Fix warning in sync_generator1_test.dart"

tests/language/sync_generator1_test.dart

Index: tests/language/sync_generator1_test.dart
diff --git a/tests/language/sync_generator1_test.dart b/tests/language/sync_generator1_test.dart
index 365e6bd90bda39abd5ae7ca5fb62eb7b5ae8c8a3..6c2b7d701ebc1142551a2b8b80aafafab5546663 100644
--- a/tests/language/sync_generator1_test.dart
+++ b/tests/language/sync_generator1_test.dart
@@ -43,7 +43,8 @@ einsZwei() sync* {
 }
 
 dreiVier() sync* {
-  yield* 3;  // Throws type error: yielded object is not an iterable.
+  // Throws type error: yielded object is not an iterable.
+  yield* 3; /// 01: static type warning
 }
 
 main() {
@@ -79,6 +80,6 @@ main() {
     print(einsZwei());
     Expect.equals("(1, 2, 3, 5, [6])", einsZwei().toString());
 
-    Expect.throws(() => dreiVier().toString());
+    Expect.throws(() => dreiVier().toString()); /// 01: continued
   }
 }