State circuit "start" tag constraints fix

[ed255]

Currently the constraints for the Start tag are:

def check_start(row: Row, row_prev: Row):
    # 1.0. rw_counter is 0
    assert row.rw_counter == 0

We defined to have sequential rwc in Start to prove a lower bound on padding rows. And there should be also more constraints verifying that some of the columns are 0, that the root doesn't change, etc.

See https://github.com/privacy-scaling-explorations/zkevm-circuits/blob/7d2c05146baaf8662d607574c44a796127e80c16/zkevm-circuits/src/state_circuit/constraint_builder.rs#L161 for reference (as this is correctly done in the circuit)

Spotted this issue here https://github.com/privacy-scaling-explorations/zkevm-circuits/pull/766#discussion_r972159319

[aguzmant103]

Just assigned to ash this week. In progress

[aguzmant103]

Note: created PR and is in review. #339