[presubmit] Enable readability/namespace linter checking.

test/unittests/compiler/register-allocator-unittest.cc

Index: test/unittests/compiler/register-allocator-unittest.cc
diff --git a/test/unittests/compiler/register-allocator-unittest.cc b/test/unittests/compiler/register-allocator-unittest.cc
index 23a118b6ad157783b13d7fe85cc3fd7613adabde..75942b6854b9a6c60d1a619d7cee34ff07e9e5ae 100644
--- a/test/unittests/compiler/register-allocator-unittest.cc
+++ b/test/unittests/compiler/register-allocator-unittest.cc
@@ -75,7 +75,8 @@ bool IsParallelMovePresent(int instr_index, Instruction::GapPosition gap_pos,
   }
   return found_match;
 }
-}
+
+}  // namespace
 
 
 class RegisterAllocatorTest : public InstructionSequenceTest {
@@ -722,7 +723,8 @@ class SlotConstraintTest : public RegisterAllocatorTest,
  private:
   typedef ::testing::WithParamInterface<::testing::tuple<ParameterType, int>> B;
 };
-}
+
+}  // namespace
 
 
 #if GTEST_HAS_COMBINE