[presubmit] Enable readability/namespace linter checking.

src/compiler/verifier.h

 // Copyright 2014 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_COMPILER_VERIFIER_H_
 #define V8_COMPILER_VERIFIER_H_
 
 #include "src/base/macros.h"
 
 namespace v8 {
@@ skipping 38 matching lines @@
  private:
   class Visitor;
   DISALLOW_COPY_AND_ASSIGN(Verifier);
 };
 
 // Verifies properties of a schedule, such as dominance, phi placement, etc.
 class ScheduleVerifier {
  public:
   static void Run(Schedule* schedule);
 };
-}
-}
-}  // namespace v8::internal::compiler
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_COMPILER_VERIFIER_H_