[presubmit] Enable readability/namespace linter checking.

src/mips/simulator-mips.h

Index: src/mips/simulator-mips.h
diff --git a/src/mips/simulator-mips.h b/src/mips/simulator-mips.h
index bd30172d5b917db52588153bcce2762298301abf..796d08fc2700c351465ac26635a1df8fbd231b27 100644
--- a/src/mips/simulator-mips.h
+++ b/src/mips/simulator-mips.h
@@ -55,7 +55,8 @@ class SimulatorStack : public v8::internal::AllStatic {
   static inline void UnregisterCTryCatch() { }
 };
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 // Calculated the stack limit beyond which we will throw stack overflow errors.
 // This macro must be called from a C++ method. It relies on being able to take
@@ -480,7 +481,8 @@ class SimulatorStack : public v8::internal::AllStatic {
   }
 };
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // !defined(USE_SIMULATOR)
 #endif  // V8_MIPS_SIMULATOR_MIPS_H_