Fix cpplint whitespace/comments issues

Change-Id: Iae286862c85fb8fd8901eae1204cd6d271d69496
diff --git a/runtime/dex_instruction_list.h b/runtime/dex_instruction_list.h
index 31d51c9..c2cd65a 100644
--- a/runtime/dex_instruction_list.h
+++ b/runtime/dex_instruction_list.h
@@ -302,4 +302,4 @@
   V(k51l)
 
 #endif  // ART_RUNTIME_DEX_INSTRUCTION_LIST_H_
-#undef ART_RUNTIME_DEX_INSTRUCTION_LIST_H_ // the guard in this file is just for cpplint
+#undef ART_RUNTIME_DEX_INSTRUCTION_LIST_H_  // the guard in this file is just for cpplint