[presubmit] Enable readability/namespace linter checking.

src/mips64/simulator-mips64.h

Index: src/mips64/simulator-mips64.h
diff --git a/src/mips64/simulator-mips64.h b/src/mips64/simulator-mips64.h
index 75d4935b74d538f73c8b4661cc2a7a20ab636b91..c470bac03df0a8c7484b73d44e800d57d1321c1e 100644
--- a/src/mips64/simulator-mips64.h
+++ b/src/mips64/simulator-mips64.h
@@ -84,7 +84,8 @@ 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
@@ -525,7 +526,8 @@ class SimulatorStack : public v8::internal::AllStatic {
   }
 };
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // !defined(USE_SIMULATOR)
 #endif  // V8_MIPS_SIMULATOR_MIPS_H_