Upstream has released updates that appear to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing
Bukkit Changes:
7da4c0be SPIGOT-6729: Add Chunk.isEntitiesLoaded()
CraftBukkit Changes:
9217b523 #929: Call EntityBlockFormEvent for Wither Rose placed by dead entity
757d42ae SPIGOT-6729: Add Chunk.isEntitiesLoaded()