Fix/improve tests (#1541)
Fix/improve tests (#1541)

* Add v:throwpoint when cleaning windows failed

* Fix s:AssertNeomakeMessage and improve non-empty-queue msg
euclio/neomake,euclio/neomake,codeinabox/neomake,nerdrew/neomake,neomake/neomake,neomake/neomake,nerdrew/neomake