message: Do not track volatile fields
  Summary: Small adjustment. Let's not mess with volatile, since IPCP excludes them as well.
diff: @@ -98,7 +98,7 @@ WholeProgramState::WholeProgramState(
  // We assume that a field we cannot delete is marked by a Proguard keep rule
  // or an annotation. The reason behind is that the field is referenced by
  // non-dex code.
  - if (!can_delete(field)) {
  + if (!can_delete(field) || field->is_external() || is_volatile(field)) {
  return;
  }
  m_known_fields.emplace(field);
  