new classes: change semantics of super(...) call and add new.target to construct stub.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index 544b4dd4595d0a07ec6a23a30bdc062882c5c4bc..038722675e372a6b830ebb80f566e671a33dd0d5 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -785,8 +785,8 @@ static void ThrowSuperConstructorCheckError(CompilationInfo* info,
 
 static bool CheckSuperConstructorCall(CompilationInfo* info) {
   FunctionLiteral* function = info->function();
+  if (FLAG_experimental_classes) return true;
   if (!function->uses_super_constructor_call()) return true;
-
   if (function->is_default_constructor()) return true;
 
   ZoneList<Statement*>* body = function->body();
@@ -836,7 +836,6 @@ static bool CheckSuperConstructorCall(CompilationInfo* info) {
     ThrowSuperConstructorCheckError(info, stmt);
     return false;
   }
-
   return true;
 }