Revert "Add native_testing library to mock @Native classes"

tests/compiler/dart2js_native/native_field_invocation2_test.dart

Index: tests/compiler/dart2js_native/native_field_invocation2_test.dart
diff --git a/tests/compiler/dart2js_native/native_field_invocation2_test.dart b/tests/compiler/dart2js_native/native_field_invocation2_test.dart
index 05e2eab6eae435fddffea153b9115f1e45fecdd1..290a68fa45b6b515bfd5e6870347285e101d6d20 100644
--- a/tests/compiler/dart2js_native/native_field_invocation2_test.dart
+++ b/tests/compiler/dart2js_native/native_field_invocation2_test.dart
@@ -2,7 +2,8 @@
 // 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 "native_testing.dart";
+import "dart:_js_helper";
+import "package:expect/expect.dart";
 
 @Native("NNative")
 class NNative {
@@ -10,9 +11,19 @@ class NNative {
 
   var f;
 
+  ClickCounter() {
+    f = wrap(g);
+  }
+
   g(val) => "### $val ###";
 }
 
+nativeId(x) native ;
+
+void setup() native """
+nativeId = function(x) { return x; }
+""";
+
 class ClickCounter {
   var status;
 
@@ -31,13 +42,6 @@ wrap(cb) {
   };
 }
 
-nativeId(x) native ;
-
-void setup() native """
-nativeId = function(x) { return x; }
-""";
-
-
 main() {
   setup();
   // Make sure the ClickCounter class goes through interceptors.