cJSON_Utils: sort_lists: Properly split the lists
cJSON_Utils: sort_lists: Properly split the lists

Since `prev` is not used anymore after that by the algorithm it should
have been fine anyways, still splitting it correctly in the first place
is probably a good idea.
Thanks @andysCaplin for the fix!

FSMaxB/cJSON,DaveGamble/cJSON,FSMaxB/cJSON,FSMaxB/cJSON,DaveGamble/cJSON,DaveGamble/cJSON,FSMaxB/cJSON,DaveGamble/cJSON,FSMaxB/cJSON