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 ac998f9c34c23ff24de6a0bf8664ef5380a77a67..62562545e50dbbcf5c76e6609df31dffb552cace 100644
--- a/lib/compiler/implementation/compile_time_constants.dart
+++ b/lib/compiler/implementation/compile_time_constants.dart
@@ -752,16 +752,17 @@ class ConstructorEvaluator extends CompileTimeConstantEvaluator {
       if (enclosingClass != compiler.objectClass) {
         assert(superClass !== null);
         assert(superClass.resolutionState == STATE_DONE);
+
+        Selector selector = new Selector.callConstructor(
+            new SelectorName.namedClass(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>(),