test(windowCount): add test asserting window Subject is disposed
test(windowCount): add test asserting window Subject is disposed

Add test for windowCount operator, to verify that every window Subject is disposed when the outer
Observable is unsubscribed.

justinwoo/RxJS,figueredo/RxJS,gluck/RxJS,ReactiveX/RxJS,jadbox/RxJS,elliotschi/rxjs,figueredo/RxJS,kwonoj/RxJS,martinsik/rxjs,RxJS-CN/RxJS-Docs-CN,adrianomelo/RxJSNext,gluck/RxJS,justinwoo/RxJS,jayphelps/rxjs,jayphelps/rxjs,martinsik/rxjs,ReactiveX/rxjs,ReactiveX/rxjs,Brocco/RxJS,Igorbek/rxjs5,adrianomelo/RxJSNext,jinroh/RxJS,saneyuki/RxJS,Brocco/RxJS,adrianomelo/RxJSNext,staltz/RxJSNext,jadbox/RxJS,martinsik/rxjs,justinwoo/RxJS,SangKa/RxJS-Docs-CN,justinwoo/RxJS,ReactiveX/rxjs,trxcllnt/RxJS,adrianomelo/RxJSNext,robwormald/RxJS,jayphelps/rxjs,Igorbek/rxjs5,benlesh/RxJS,RxJS-CN/RxJS-Docs-CN,jayphelps/rxjs,staltz/RxJSNext,ReactiveX/RxJS,jinroh/RxJS,SangKa/RxJS-Docs-CN,jadbox/RxJS,staltz/RxJSNext,elliotschi/rxjs,gluck/RxJS,jinroh/RxJS,elliotschi/rxjs,SangKa/RxJS-Docs-CN,kwonoj/RxJS,ReactiveX/RxJS,IgorMinar/RxJS,saneyuki/RxJS,benlesh/RxJS,RxJS-CN/RxJS-Docs-CN,gluck/RxJS,Igorbek/rxjs5,martinsik/rxjs,robwormald/RxJS,ReactiveX/RxJS,SangKa/RxJS-Docs-CN,trxcllnt/RxJS,jayphelps/rxjs,kwonoj/RxJS,RxJS-CN/RxJS-Docs-CN,adrianomelo/RxJS-1,figueredo/RxJS,robwormald/RxJS,benlesh/RxJS,adrianomelo/RxJS-1,adrianomelo/RxJS-1,Brocco/RxJS,IgorMinar/RxJS,kwonoj/RxJS,jinroh/RxJS,staltz/RxJSNext,elliotschi/rxjs,adrianomelo/RxJS-1,trxcllnt/RxJS,jadbox/RxJS,figueredo/RxJS,trxcllnt/RxJS,Igorbek/rxjs5,ReactiveX/rxjs,Brocco/RxJS,robwormald/RxJS,benlesh/RxJS