Use native packer to transfer globals into async env(s)

builtin/async/game.lua

@@ -22,8 +22,7 @@ dofile(gamepath .. "voxelarea.lua")
 
 -- Transfer of globals
 do
-	assert(core.transferred_globals)
-	local all = core.deserialize(core.transferred_globals, true)
+	local all = assert(core.transferred_globals)
 	core.transferred_globals = nil
 
 	-- reassemble other tables

builtin/game/misc.lua

@@ -262,5 +262,5 @@ function core.get_globals_to_transfer()
 		registered_items = copy_filtering(core.registered_items),
 		registered_aliases = core.registered_aliases,
 	}
-	return core.serialize(all)
+	return all
 end