Fix yield statements in catch blocks

tests/language/sync_generator3_test.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Test program for sync* generator functions and yielding in try blocks.
+
+import "package:expect/expect.dart";
+
+f() sync* {
+  try {
+    yield 1;
+    throw "three";
+  } catch (e) {
+    yield 2;
+    yield e;
+  } finally {
+    yield 4;
+  }
+}
+
+test1() {
+  var s = f().toString();
+  Expect.equals("(1, 2, three, 4)", s);
+  print(s);
+}
+
+g() sync* {
+  try {
+    yield "a";
+    throw "pow!";
+  } finally {
+    yield "b";
+  }
+}
+
+test2() {
+  var s;
+  try {
+    s = g().toString();
+  } catch (e) {
+    Expect.equals("pow!", e);
+    Expect.equals("(a, b)", s);
+    print(s);
+  }
+}
+
+main() {
+  test1();  /// test1: ok
+  test2();  /// test2: ok
+}