* op-node: sync start update func signature, port over tests from safe-head-fix pr

* op-node: sync start now starts with current heads by label

* op-node: single loop find-heads

* op-node: sync - clean up go doc

* op-node: use sync fn in engine queue

* op-node: fix engine queue finalization test

* op-node: sync off-by-one fix

* op-node: fix highest l2 block with canon origin, need to reset when l1 reorg

* op-node: handle non-standard safe/finalized not found errors

* op-node: sync start review fixes / comment typos

* op-node: seq window size check with l1 origin, update engine queue test with extra l1 origin, now that off by 1 fix applies properly to chains with multiple L2 blocks per L1 block

* op-node: start from parent block before seq nr 0

* Update op-node/rollup/sync/start.go
Co-authored-by: Joshua Gutow <jgutow@optimism.io>

* review fixes

* fix lint
Co-authored-by: Joshua Gutow <jgutow@optimism.io>
Co-authored-by: Matthew Slipper <me@matthewslipper.com>