Port transaction validation tests to new function
https://github.com/status-im/nimbus-eth1/blob/d6eb8c36f5ae655bb4a0159efa41bff6b113b527/nimbus/transaction.nim#L157 contains a transaction validation function that has fallen out of use.

The old function however has a set of checks and validations that the new function does not have - it also has test coverage which is missing from the new function - both of these issues need to be address such that the old tests and validations are checked.
