Address some comments

Change-Id: I0262304cc720a0e93015955d0a7fb05dfebe213e
diff --git a/runtime/gc/heap.cc b/runtime/gc/heap.cc
index 59e39df..e9d9065 100644
--- a/runtime/gc/heap.cc
+++ b/runtime/gc/heap.cc
@@ -2912,7 +2912,7 @@
           if (!obj->IsObjectArray()) {
             mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass();
             CHECK(klass != nullptr);
-            for (ArtField& field : is_static ? klass->GetSFields() : klass->GetIFields()) {
+            for (ArtField& field : (is_static ? klass->GetSFields() : klass->GetIFields())) {
               if (field.GetOffset().Int32Value() == offset.Int32Value()) {
                 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is "
                            << PrettyField(&field);