Revert "Add native_testing library to mock @Native classes"

tests/compiler/dart2js_native/native_method_rename1_frog_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 the feature where the native string declares the native method's name.
 
-import 'native_testing.dart';
+import "package:expect/expect.dart";
 import 'dart:_js_helper' show Native, JSName;
 
 @Native("A")
 class A {
   @JSName('fooA')
   int foo() native ;
 
   @JSName('barA')
   int bar() native ;
 
   @JSName('bazA')
   int baz() native ;
 }
 
 A makeA() native ;
 
 class B {
   int bar([x]) => 800;
   int baz() => 900;
 }
 
 void setup() native """
 // This code is all inside 'setup' and so not accesible from the global scope.
 function A(){}
 A.prototype.fooA = function(){return 100;};
 A.prototype.barA = function(){return 200;};
 A.prototype.bazA = function(){return 300;};
 
 makeA = function(){return new A};
-
-self.nativeConstructor(A);
 """;
 
 testDynamic() {
-  var a = confuse(makeA());
-  var b = confuse(new B());
+  setup();
+
+  var things = [makeA(), new B()];
+  var a = things[0];
+  var b = things[1];
 
   Expect.equals(100, a.foo());
   Expect.equals(200, a.bar());
   Expect.equals(300, a.baz());
   Expect.equals(800, b.bar());
   Expect.equals(900, b.baz());
 }
 
 testTyped() {
   A a = makeA();
   B b = new B();
 
   Expect.equals(100, a.foo());
   Expect.equals(200, a.bar());
   Expect.equals(300, a.baz());
   Expect.equals(800, b.bar());
   Expect.equals(900, b.baz());
 }
 
 main() {
-  nativeTesting();
   setup();
   testDynamic();
   testTyped();
 }
 
 expectNoSuchMethod(action, note) {
   bool caught = false;
   try {
     action();
   } catch (ex) {
     caught = true;
     Expect.isTrue(ex is NoSuchMethodError, note);
   }
   Expect.isTrue(caught, note);
 }