message: fix become_virtual
  Summary:
  This method isn't called, but there was definitely a bug in it
  See discussion on the github issue.
  Fixes
diff: @@ -566,10 +566,10 @@ void DexClass::remove_method(const DexMethod* m) {
  void DexMethod::become_virtual() {
  assert(!m_virtual);
  - m_virtual = true;
  auto cls = type_class(m_spec.cls);
  assert(!cls->is_external());
  cls->remove_method(this);
  + m_virtual = true;
  auto& vmethods = cls->get_vmethods();
  insert_sorted(vmethods, this, compare_dexmethods);
  }
  