[presubmit] Enable readability/namespace linter checking.

test/cctest/test-api-interceptors.cc

 // Copyright 2015 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.
 
 #include <stdlib.h>
 
 #include "test/cctest/test-api.h"
 
 #include "include/v8-util.h"
 #include "src/api.h"
@@ skipping 3233 matching lines @@
   ApiTestFuzzer::Fuzz();
   auto context = info.GetIsolate()->GetCurrentContext();
   if (name->Equals(v8_str("db"))) return;
   Local<v8::Object> db = info.Holder()
                              ->GetRealNamedProperty(context, v8_str("db"))
                              .ToLocalChecked()
                              .As<v8::Object>();
   db->Set(context, name, value).FromJust();
   info.GetReturnValue().Set(value);
 }
-}
+
+}  // namespace
 
 
 THREADED_TEST(NonMaskingInterceptorGlobalEvalRegression) {
   auto isolate = CcTest::isolate();
   v8::HandleScope handle_scope(isolate);
   LocalContext context;
 
   auto interceptor_templ = v8::ObjectTemplate::New(isolate);
   v8::NamedPropertyHandlerConfiguration conf(DatabaseGetter, DatabaseSetter);
   conf.flags = v8::PropertyHandlerFlags::kNonMasking;
@@ skipping 13 matching lines @@
       "var obj = intercepted_1;"
       "obj.x = 4;"
       "eval('obj.x');"
       "eval('obj.x');"
       "eval('obj.x');"
       "obj = intercepted_2;"
       "obj.x = 9;"
       "eval('obj.x');",
       9);
 }