ART: Add missing namespace comments

Add closing namespace comments.

Bug: 32619234
Test: m
Change-Id: I1f50e09dcd1038c4b540b87e5c19e319c1f592e4
diff --git a/compiler/driver/compiler_options.h b/compiler/driver/compiler_options.h
index 5a82021..89c2537 100644
--- a/compiler/driver/compiler_options.h
+++ b/compiler/driver/compiler_options.h
@@ -31,7 +31,7 @@
 
 namespace verifier {
   class VerifierDepsTest;
-}
+}  // namespace verifier
 
 class DexFile;