erts: Change gc of boxed to store fwd ptr in second word
Start working on merging boxed and cons
Start work on making {} into an immidiate
Start work on cdr encoding for lists
Revert All incomplete cdr encoding work

This reverts commit ba449b481abb682b601036129ed8e4ca46d29980.
This reverts commit f51adf60ff7d72ec2d27fb6587dfe9e55cd286f3.
This reverts commit ba1c56750e37a6e8926882b465e0fc937be5b88a.
Fix heap check function
Change tnv to be a NIL subvalue
Expand heapdump with boxed types
Fix zero tuple
tuple-0 work
polish validation
Debug stash