[presubmit] Enable readability/namespace linter checking.

src/preparser.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PREPARSER_H
 #define V8_PREPARSER_H
 
 #include "src/bailout-reason.h"
 #include "src/expression-classifier.h"
 #include "src/func-name-inferrer.h"
@@ skipping 4165 matching lines @@
     }
     if (has_seen_constructor_) {
       this->parser()->ReportMessage(MessageTemplate::kDuplicateConstructor);
       *ok = false;
       return;
     }
     has_seen_constructor_ = true;
     return;
   }
 }
-} }  // v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_PREPARSER_H