* Adding L1MessageSender to Transaction
* Adding logic to omit L1MessageSender in encoding / decoding when nil and never use it in hash computation
Co-authored-by: ben-chain <ben@pseudonym.party>
* core: speed up GenerateChain
Use a mock implementation of ChainReader instead of creating
and destroying a BlockChain object for each generated block.
* eth/downloader: speed up tests by generating chain only once
This change reworks the downloader tests so they share a common test
blockchain instead of generating a chain in every test. The tests are
roughly twice as fast now.
