Force base weights to be the minimum only when the intercept is negative (#12482)

* Force base weights to be the minimum only when the intercept is negative; emit minimum execution times

* Add an `assert` making sure the intercept is zero when it's supposed to be zero

* Fix template

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* ".git/.scripts/bench-bot.sh" pallet dev pallet_assets

* ".git/.scripts/bench-bot.sh" pallet dev pallet_uniques

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: command-bot <>