[presubmit] Enable readability/namespace linter checking.

test/cctest/test-asm-validator.cc

Index: test/cctest/test-asm-validator.cc
diff --git a/test/cctest/test-asm-validator.cc b/test/cctest/test-asm-validator.cc
index 0cc71ec2f54fbc84fda2fe2398807ef1ca20e51f..7b45a673f39d65d1a492e3f265cd3a3575028d98 100644
--- a/test/cctest/test-asm-validator.cc
+++ b/test/cctest/test-asm-validator.cc
@@ -74,7 +74,8 @@ std::string Validate(Zone* zone, const char* source,
     return typer.error_message();
   }
 }
-}
+
+}  // namespace
 
 
 TEST(ValidateMinimum) {
@@ -439,7 +440,8 @@ void CheckStdlibShortcuts(Zone* zone, ZoneVector<ExpressionTypeEntry>& types,
   CHECK_VAR_NEW_SHORTCUT(f32, Bounds(cache.kFloat32Array));
   CHECK_VAR_NEW_SHORTCUT(f64, Bounds(cache.kFloat64Array));
 }
-}
+
+}  // namespace
 
 
 #define CHECK_FUNC_TYPES_BEGIN(func)                   \