Revert "Fix runtimeType.toString for tear-offs."

tests/language/runtime_type2_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.
-
-import "package:expect/expect.dart";
-
-class A {
-  foo() => 499;
-}
-
-bar() => 42;
-
-main() {
-  String runtimeStringFoo = new A().foo.runtimeType.toString();
-  String runtimeStringBar = bar.runtimeType.toString();
-  // Check for the VM string, the unminified dart2js string, and a short
-  // string (in case it was minified).
-  Expect.isTrue(
-      runtimeStringFoo == "() => dynamic" ||
-      runtimeStringFoo == "BoundClosure" ||
-      new RegExp('[a-zA-Z]{1,3}').hasMatch(runtimeStringFoo));
-  Expect.isTrue(
-      runtimeStringBar == "() => dynamic" ||
-      runtimeStringBar == "StaticClosure" ||
-      new RegExp('[a-zA-Z]{1,3}').hasMatch(runtimeStringFoo));
-}