message: Add slow check that all methods in code are in context
  Summary: As title.
diff: @@ -1172,13 +1172,33 @@ void PassManager::run_passes(DexStoresVector& stores, ConfigFiles& conf) {
  };
  auto post_pass_verifiers = [&](Pass* pass, size_t i, size_t size) {
  - walk::parallel::code(build_class_scope(stores), [](DexMethod* m,
  + ConcurrentSet<const DexMethodRef*> all_code_referenced_methods;
  + walk::parallel::code(build_class_scope(stores), [&](DexMethod* m,
  IRCode& code) {
  // Ensure that pass authors deconstructed the editable CFG at the end of
  // their pass. Currently, passes assume the incoming code will be in
  // IRCode form
  always_assert_log(!code.editable_cfg_built(), "%s has a cfg!", SHOW(m));
  + if (slow_invariants_debug) {
  + std::vector<DexMethodRef*> methods;
  + methods.reserve(1000);
  + methods.push_back(m);
  + code.gather_methods(methods);
  + for (auto* mref : methods) {
  + always_assert_log(
  + DexMethod::get_method(mref->get_class(), mref->get_name(),
  + mref->get_proto()) != nullptr,
  + "Did not find %s in the context, referenced from %s!", SHOW(mref),
  + SHOW(m));
  + all_code_referenced_methods.insert(mref);
  + }
  + }
  });
  + if (slow_invariants_debug) {
  + ScopedMetrics sm(*this);
  + sm.set_metric("num_code_referenced_methods",
  + all_code_referenced_methods.size());
  + }
  bool run_hasher = run_hasher_after_each_pass;
  bool run_assessor = assessor_config.run_after_each_pass ||
  