[es6] new.target should not be shadowable in a with scope

src/ast.h

Index: src/ast.h
diff --git a/src/ast.h b/src/ast.h
index 0e419c564dd4a2047925c49774b9b100e1901a2a..f9d7af1e0d70d624d2f88372b75facba3e6f27ee 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -2827,7 +2827,7 @@ class SuperCallReference final : public Expression {
         new_target_var_(new_target_var),
         this_function_var_(this_function_var) {
     DCHECK(this_var->is_this());
-    DCHECK(new_target_var->raw_name()->IsOneByteEqualTo("new.target"));
+    DCHECK(new_target_var->raw_name()->IsOneByteEqualTo(".new.target"));
     DCHECK(this_function_var->raw_name()->IsOneByteEqualTo(".this_function"));
   }