Currently we hard-code weights for System::set_code and System::set_code_without_checks:

#[pallet::call_index(2)]
#[pallet::weight((T::BlockWeights::get().max_block, DispatchClass::Operational))]
pub fn set_code(origin: OriginFor<T>, code: Vec<u8>) -> DispatchResultWithPostInfo {

This is inflexible and always results in un-schedulable runtime upgrades. We should benchmark them instead.

cc @gavofyork