Add constructors for JSArray

tests/compiler/dart2js/value_range_test.dart

 // Copyright (c) 2012, 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 "package:expect/expect.dart";
 import 'compiler_helper.dart';
 
 const int REMOVED = 0;
 const int ABOVE_ZERO = 1;
 const int BELOW_LENGTH = 2;
@@ skipping 274 matching lines @@
   class Interceptor {
     toString() {}
     bool operator==(other) => identical(this, other);
     noSuchMethod(im) { throw im; }
   }
   abstract class JSIndexable {
     get length;
   }
   abstract class JSMutableIndexable extends JSIndexable {}
   class JSArray implements JSIndexable {
+    JSArray() {}
+    JSArray.typed(a) => a;
     var length;
     var removeLast;
     operator[] (_) {}
   }
   class JSMutableArray extends JSArray implements JSMutableIndexable {}
   class JSFixedArray extends JSMutableArray {}
   class JSExtendableArray extends JSMutableArray {}
   class JSString implements JSIndexable {
     var length;
   }
@@ skipping 72 matching lines @@
       break;
   }
 }
 
 
 main() {
   for (int i = 0; i < TESTS.length;  i += 2) {
     expect(TESTS[i], TESTS[i + 1]);
   }
 }