fix list_test for strong mode, and fix DDC List constructors

pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/classes.dart

 // Copyright (c) 2015, 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.
 
 /// This library defines the operations that define and manipulate Dart
 /// classes.  Included in this are:
 ///   - Generics
 ///   - Class metadata
 ///   - Extension methods
 ///
@@ skipping 513 matching lines @@
       }
       return sig;
     });
   };
   upgradeSig($_methodSig);
   upgradeSig($_fieldSig);
   upgradeSig($_getterSig);
   upgradeSig($_setterSig);
 })()''');
 
-/// Sets the type of `obj` to be `type`
-setType(obj, type) {
-  JS('', '#.__proto__ = #.prototype', obj, type);
-  return obj;
-}
-
 /// Link the extension to the type it's extending as a base class.
 setBaseClass(derived, base) {
   JS('', '#.prototype.__proto__ = #.prototype', derived, base);
   // We use __proto__ to track the superclass hierarchy (see isSubtype).
   JS('', '#.__proto__ = #', derived, base);
 }
 
 /// Like [setBaseClass], but for generic extension types such as `JSArray<E>`.
 setExtensionBaseClass(dartType, jsType) {
   // Mark the generic type as an extension type and link the prototype objects.
   var dartProto = JS('', '#.prototype', dartType);
   JS('', '#[#] = #', dartProto, _extensionType, dartType);
   JS('', '#.__proto__ = #.prototype', dartProto, jsType);
 }
 
 defineEnumValues(enumClass, names) {
   var values = [];
   for (var i = 0; i < JS('int', '#.length', names); i++) {
     var value = const_(JS('', 'new #.new(#)', enumClass, i));
     JS('', '#.push(#)', values, value);
     defineValue(enumClass, JS('', '#[#]', names, i), value);
   }
   JS('', '#.values = #', enumClass, constList(values, enumClass));
 }