fix(anvil): deterministic block production

[fubhy]

Motivation

Anvil block production should be deterministic to allow for more convenient integration testing on top of anvil.

Solution

Avoid using a random value for prevandao.

PR Checklist

• Added Tests

Fixes #9570

[zerosnacks]

This makes sense to me

Adding label to mark this as a breaking change as users may expect to have been able to use prevrandao as a randomness beacon and this will no longer be true

[mattsse]

ah I see, randao is then derived from the chain

this makes sense to me, this way the hash is still changing and shouldn't cause any issue, because previously this was just fully random