Add regression tests from Luke's bug reports. Part 2.

pkg/front_end/testcases/regress/issue_29942.dart

Index: pkg/front_end/testcases/regress/issue_29942.dart
diff --git a/pkg/front_end/testcases/regress/issue_29942.dart b/pkg/front_end/testcases/regress/issue_29942.dart
new file mode 100644
index 0000000000000000000000000000000000000000..6117e0969eb2bc78861e671547ec8490ec6e9323
--- /dev/null
+++ b/pkg/front_end/testcases/regress/issue_29942.dart
@@ -0,0 +1,10 @@
+// Copyright (c) 2017, 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.
+
+main() {
+}
+
+f() =
+
+h() => null;