dart2js_native tests: Migrate 'native STRING' to JS-calls

tests/compiler/dart2js_native/native_class_inheritance3_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.
 
 import "native_testing.dart";
 
 // Test to see if resolving a hidden native class's method to noSuchMethod
 // interferes with subsequent resolving of the method.  This might happen if the
 // noSuchMethod is cached on Object.prototype.
 
@@ skipping 12 matching lines @@
 }
 
 @Native("B2")
 class B2 extends A2 {}
 
 makeA2() native;
 makeB2() native;
 
 makeObject() native;
 
-void setup() native """
-// This code is all inside 'setup' and so not accessible from the global scope.
-function inherits(child, parent) {
-  if (child.prototype.__proto__) {
-    child.prototype.__proto__ = parent.prototype;
-  } else {
-    function tmp() {};
-    tmp.prototype = parent.prototype;
-    child.prototype = new tmp();
-    child.prototype.constructor = child;
+void setup() {
+  JS('', r"""
+(function(){
+  // This code is inside 'setup' and so not accessible from the global scope.
+  function inherits(child, parent) {
+    if (child.prototype.__proto__) {
+      child.prototype.__proto__ = parent.prototype;
+    } else {
+      function tmp() {};
+      tmp.prototype = parent.prototype;
+      child.prototype = new tmp();
+      child.prototype.constructor = child;
+    }
   }
+  function A1(){}
+  function B1(){}
+  inherits(B1, A1);
+
+  makeA1 = function(){return new A1()};
+  makeB1 = function(){return new B1()};
+
+  function A2(){}
+  function B2(){}
+  inherits(B2, A2);
+  A2.prototype.foo = function(a){return 'A2.foo(' + a  + ')';};
+
+  makeA2 = function(){return new A2()};
+  makeB2 = function(){return new B2()};
+
+  makeObject = function(){return new Object()};
+
+  self.nativeConstructor(A1);
+  self.nativeConstructor(A2);
+  self.nativeConstructor(B1);
+  self.nativeConstructor(B2);
+})()""");
 }
-function A1(){}
-function B1(){}
-inherits(B1, A1);
-
-makeA1 = function(){return new A1};
-makeB1 = function(){return new B1};
-
-function A2(){}
-function B2(){}
-inherits(B2, A2);
-A2.prototype.foo = function(a){return 'A2.foo(' + a  + ')';}
-
-makeA2 = function(){return new A2};
-makeB2 = function(){return new B2};
-
-makeObject = function(){return new Object};
-
-self.nativeConstructor(A1);
-self.nativeConstructor(A2);
-self.nativeConstructor(B1);
-self.nativeConstructor(B2);
-""";
 
 main() {
   nativeTesting();
   setup();
 
   var a1 = makeA1();
   var b1 = makeB1();
   var ob = makeObject();
 
   // Does calling missing methods in one tree of inheritance forest affect other
@@ skipping 17 matching lines @@
 expectNoSuchMethod(action, note) {
   bool caught = false;
   try {
     action();
   } catch (ex) {
     caught = true;
     Expect.isTrue(ex is NoSuchMethodError, note);
   }
   Expect.isTrue(caught, note);
 }