Move out `process_result_queue` from cycle in `LdaMulticore` (#2358)
Move out `process_result_queue` from cycle in `LdaMulticore` (#2358)

* Move out `process_result_queue`

+ simplify inner check
+ add heuristic for case with large number of workers

* delete heuristic

* swap branches in if self.batch check

gojomo/gensim,RaRe-Technologies/gensim,gojomo/gensim,piskvorky/gensim,piskvorky/gensim,gojomo/gensim,gojomo/gensim,piskvorky/gensim,RaRe-Technologies/gensim,RaRe-Technologies/gensim,RaRe-Technologies/gensim