Made dart2js constructor lookup logic "private"-aware, fixed 4740 bug.

lib/compiler/implementation/compile_time_constants.dart

Index: lib/compiler/implementation/compile_time_constants.dart
diff --git a/lib/compiler/implementation/compile_time_constants.dart b/lib/compiler/implementation/compile_time_constants.dart
index 411b90b11eaf76e8d644e8876d97808aa31705ea..a4d4cf2ad956308ceac705cc65fe84657fef19f4 100644
--- a/lib/compiler/implementation/compile_time_constants.dart
+++ b/lib/compiler/implementation/compile_time_constants.dart
@@ -769,16 +769,17 @@ class ConstructorEvaluator extends CompileTimeConstantEvaluator {
       if (enclosingClass != compiler.objectClass) {
         assert(superClass !== null);
         assert(superClass.resolutionState == STATE_DONE);
+
+        Selector selector =
+            new Selector.callDefaultConstructor(superClass.name,
+                                                enclosingClass.getLibrary());
         FunctionElement targetConstructor =
-            superClass.lookupConstructor(superClass.name);
+            superClass.lookupConstructor(selector);
         if (targetConstructor === null) {
           compiler.internalError("no default constructor available",
                                  node: functionNode);
         }
 
-        Selector selector = new Selector.call(superClass.name,
-                                              enclosingClass.getLibrary(),
-                                              0);
         evaluateSuperOrRedirectSend(functionNode,
                                     selector,
                                     const EmptyLink<Node>(),