test(operator-concat): using run mode tests (#5143)
test(operator-concat): using run mode tests (#5143)

* test(operator-concat): using run mode tests

* fixing whitespace issues

ReactiveX/rxjs,martinsik/rxjs,benlesh/RxJS,trxcllnt/RxJS,ReactiveX/rxjs,trxcllnt/RxJS,ReactiveX/rxjs,martinsik/rxjs,benlesh/RxJS,kwonoj/RxJS,trxcllnt/RxJS,ReactiveX/RxJS,ReactiveX/RxJS,martinsik/rxjs,ReactiveX/RxJS,kwonoj/RxJS,kwonoj/RxJS,benlesh/RxJS,martinsik/rxjs,benlesh/RxJS,kwonoj/RxJS,ReactiveX/RxJS,trxcllnt/RxJS,ReactiveX/rxjs