- Remove the legacy debug protocol.

tests/standalone/debugger/tostring_throws_test.dart

-// Copyright (c) 2013, 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 "debug_lib.dart";
-
-main(List<String> arguments) {
-  if (RunScript(testScript, arguments)) return;
-
-  Foo foo = new Foo();
-
-  print("Hello from debuggee");
-}
-
-class Foo {
-  String toString() {
-    throw 'I always throw';
-  }
-}
-
-// Make sure Foo.toString() does not get called.
-var testScript = [
-  MatchFrame(0, "main"),
-  SetBreakpoint(12),
-  Resume(),
-  MatchFrame(0, "main"),
-  MatchLocals({"foo": "object of type Foo"}),
-  Resume(),
-];