[presubmit] Enable readability/namespace linter checking.

src/regexp/regexp-macro-assembler-tracer.h

 // Copyright 2008 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_REGEXP_REGEXP_MACRO_ASSEMBLER_TRACER_H_
 #define V8_REGEXP_REGEXP_MACRO_ASSEMBLER_TRACER_H_
 
 #include "src/regexp/regexp-macro-assembler.h"
 
 namespace v8 {
@@ skipping 63 matching lines @@
   virtual void SetRegister(int register_index, int to);
   virtual bool Succeed();
   virtual void WriteCurrentPositionToRegister(int reg, int cp_offset);
   virtual void ClearRegisters(int reg_from, int reg_to);
   virtual void WriteStackPointerToRegister(int reg);
 
  private:
   RegExpMacroAssembler* assembler_;
 };
 
-}}  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_REGEXP_REGEXP_MACRO_ASSEMBLER_TRACER_H_