[presubmit] Enable readability/namespace linter checking.

src/arm64/simulator-arm64.h

 // Copyright 2013 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_ARM64_SIMULATOR_ARM64_H_
 #define V8_ARM64_SIMULATOR_ARM64_H_
 
 #include <stdarg.h>
 #include <vector>
 
@@ skipping 893 matching lines @@
     return sim->PushAddress(try_catch_address);
   }
 
   static void UnregisterCTryCatch() {
     Simulator::current(Isolate::Current())->PopAddress();
   }
 };
 
 #endif  // !defined(USE_SIMULATOR)
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_ARM64_SIMULATOR_ARM64_H_