[presubmit] Enable readability/namespace linter checking.

src/arm/simulator-arm.h

Index: src/arm/simulator-arm.h
diff --git a/src/arm/simulator-arm.h b/src/arm/simulator-arm.h
index a972a77d411c47480bd572bd662b625eb66f73c2..0c6aaf8c24dbc4c7a0372e235ab85c0cfca35e42 100644
--- a/src/arm/simulator-arm.h
+++ b/src/arm/simulator-arm.h
@@ -55,7 +55,8 @@ class SimulatorStack : public v8::internal::AllStatic {
   static inline void UnregisterCTryCatch() { }
 };
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #else  // !defined(USE_SIMULATOR)
 // Running with a simulator.
@@ -459,7 +460,8 @@ class SimulatorStack : public v8::internal::AllStatic {
   }
 };
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // !defined(USE_SIMULATOR)
 #endif  // V8_ARM_SIMULATOR_ARM_H_