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 bcae3b90b4db5fe2c8879c3f64d99c820e0e3ea8..c7e1572d873fec35820f36664720e91156c7696a 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -786,8 +786,8 @@ 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();
@@ -837,7 +837,6 @@ static bool CheckSuperConstructorCall(CompilationInfo* info) {
     ThrowSuperConstructorCheckError(info, stmt);
     return false;
   }
-
   return true;
 }