[presubmit] Enable readability/namespace linter checking.

test/cctest/expression-type-collector.cc

Index: test/cctest/expression-type-collector.cc
diff --git a/test/cctest/expression-type-collector.cc b/test/cctest/expression-type-collector.cc
index 9ab85edf82c8087df2922b44a718d4871859ef50..d3fa3e897314eeb8590edff90aa0880366717ce9 100644
--- a/test/cctest/expression-type-collector.cc
+++ b/test/cctest/expression-type-collector.cc
@@ -24,7 +24,8 @@ struct {
     AST_NODE_LIST(DECLARE_VISIT)
 #undef DECLARE_VISIT
 };
-}
+
+}  // namespace
 
 
 ExpressionTypeCollector::ExpressionTypeCollector(
@@ -57,5 +58,6 @@ void ExpressionTypeCollector::VisitExpression(Expression* expression) {
   }
   result_->push_back(e);
 }
-}
-}
+
+}  // namespace internal
+}  // namespace v8