[presubmit] Enable readability/namespace linter checking.

src/compiler.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_COMPILER_H_
 #define V8_COMPILER_H_
 
 #include "src/allocation.h"
 #include "src/ast.h"
 #include "src/bailout-reason.h"
@@ skipping 698 matching lines @@
  private:
   const char* name_;
   CompilationInfo* info_;
   Zone zone_;
   size_t info_zone_start_allocation_size_;
   base::ElapsedTimer timer_;
 
   DISALLOW_COPY_AND_ASSIGN(CompilationPhase);
 };
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_COMPILER_H_