message: call the right ::get_pure_methods()
  Summary: This uses a small set of statically known pure methods (instead of calling an instance method that always returns the empty set at this point, which is not what was intended).
diff: @@ -98,7 +98,7 @@ Shrinker::Shrinker(
  if (config.run_cse || config.run_local_dce) {
  if (config.compute_pure_methods) {
  - const auto& pure_methods = get_pure_methods();
  + const auto& pure_methods = ::get_pure_methods();
  m_pure_methods.insert(pure_methods.begin(), pure_methods.end());
  auto immutable_getters = get_immutable_getters(scope);
  m_pure_methods.insert(immutable_getters.begin(), immutable_getters.end());
  