fix GC safety bug in cloneTreeNode
fix GC safety bug in cloneTreeNode

joshuawarner32/avian,bigfatbrowncat/avian-pack.avian,MaartenR/avian,MaartenR/avian,minor-jason/avian,bigfatbrowncat/avian-pack.avian,joshuawarner32/avian,marcinolawski/avian,lostdj/avian,ucdseniordesign/avian,bgould/avian,ucdseniordesign/avian,ucdseniordesign/avian,bgould/avian,bgould/avian,minor-jason/avian,lwahlmeier/avian,joshuawarner32/avian,getlantern/avian,bgould/avian,getlantern/avian,lostdj/avian,lwahlmeier/avian,marcinolawski/avian,lostdj/avian,dicej/avian,marcinolawski/avian,badlogic/avian,lwahlmeier/avian,minor-jason/avian,dicej/avian,bigfatbrowncat/avian-pack.avian,ucdseniordesign/avian,dicej/avian,badlogic/avian,joshuawarner32/avian,lwahlmeier/avian,minor-jason/avian,dicej/avian,lostdj/avian,getlantern/avian,badlogic/avian,marcinolawski/avian,badlogic/avian,MaartenR/avian,getlantern/avian,MaartenR/avian,bigfatbrowncat/avian-pack.avian