Weights for parachain-system

[xlc]

Needs some benchmarking & weights for parachain-system pallet

[bkchr]

@shawntabrizi anyone that could work on this?

Especially

cumulus/pallets/parachain-system/src/lib.rs

Line 291 in ad5dd36

pub fn set_validation_data(

[bkchr]

@ggwpez could you look into this please?

[ggwpez]

If set_validation_data is only called from inherents, then it it part of the BlockExecutionWeight. But benchmarks should be added nonetheless. I will take a look.