Revert "Add native_testing library to mock @Native classes"

tests/compiler/dart2js_native/native_method_inlining_test.dart

 // Copyright (c) 2011, 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 that native methods with unnamed optional arguments are called with the
 // number of arguments in the call site AND the call site is inlined.
 
-import 'native_testing.dart';
+import "package:expect/expect.dart";
+import 'dart:_js_helper' show Native, NoInline;
 
 typedef int Int2Int(int x);
 
 @Native("A")
 class A {
   int foo([x, y, z]) native ;
 
   // Calls can be inlined provided they don't pass an argument.
   int callFun([Int2Int fn]) native ;
 }
@@ skipping 44 matching lines @@
 findMethodTextContaining = function (instance, string) {
   var proto = Object.getPrototypeOf(instance);
   var keys = Object.keys(proto);
   for (var i = 0; i < keys.length; i++) {
     var name = keys[i];
     var member = proto[name];
     var s = String(member);
     if (s.indexOf(string)>0) return s;
   }
 };
-
-self.nativeConstructor(A);
 """;
 
 bool get isCheckedMode {
   int i = 0;
   try {
     i = 'a';
   } catch (e) {
     return true;
   }
   return false;
@@ skipping 57 matching lines @@
   // Ensure the methods are compiled by calling them.
   var a = makeA();
   Expect.equals(369, a.callFun((i) => 3 * i));
 
   var b = new B();
   Expect.equals(2, b.method2());
   Expect.equals(246, b.method3());
 }
 
 main() {
-  nativeTesting();
   setup();
   test1();
   test2();
 }