Bor fixes (#3553)

* Integration to work with bor

* Turn off validator set check

* disable verifySeal, add skeleton of postExec stage

* Pass around syscall

* Print

* Print more

* Default heimdall values for integration

* restore contract

* Print

* Print

* Print

* Print

* Print

* Print

* Print

* Print

* Fix nonce of system contract

* Remove prints

* Revert some more printing

* More fixes

* Print log

* Fix transfer log

* More printing

* More printing

* Print

* Print

* Print

* Print

* Print

* Print

* Print

* Fix validaor reward

* Remove printing

* Remove more prints

* Less printing

* Fetch validators from heimdall

* Remove syscall from Seal and CalcDifficulty

* Remove syscall from Prepare

* Print

* Remove DNS discovery

* Print apply snapshot

* Print

* Chunk up snapshot generation

* Chunk up snapshot generation

* Better logs when snapshotting

* Handle parents

* Prevent shadowing of snap

* Fix heimdall fetch

* Logging fixes

* Save generated snapshots

* Add header

* Less logging

Co-authored-by: Alexey Sharp <alexeysharp@Alexeys-iMac.local>
Co-authored-by: Alex Sharp <alexsharp@Alexs-MacBook-Pro.local>