Fix reference table sorting

Bug: 18638116
Change-Id: I30894d5c33a2702b0c0be7fc9789b42256eea8b1
diff --git a/runtime/reference_table.cc b/runtime/reference_table.cc
index 70aba9b..5035463 100644
--- a/runtime/reference_table.cc
+++ b/runtime/reference_table.cc
@@ -89,7 +89,7 @@
 
     // Sort by class...
     if (obj1->GetClass() != obj2->GetClass()) {
-      return obj1->GetClass()->IdentityHashCode() < obj2->IdentityHashCode();
+      return obj1->GetClass()->IdentityHashCode() < obj2->GetClass()->IdentityHashCode();
     } else {
       // ...then by size...
       size_t count1 = obj1->SizeOf();