test(tests/lean/hott): add test for 'cases' tactic
test(tests/lean/hott): add test for 'cases' tactic

fgdorais/lean,Kha/lean,eigengrau/lean,fpvandoorn/lean2,fgdorais/lean,leanprover-community/lean,digama0/lean,fgdorais/lean,soonhokong/lean,leanprover/lean,fpvandoorn/lean,leodemoura/lean,c-cube/lean,fpvandoorn/lean2,leanprover/lean,johoelzl/lean,sp3ctum/lean,avigad/lean,sp3ctum/lean,htzh/lean,dselsam/lean,eigengrau/lean,sp3ctum/lean,fpvandoorn/lean,soonhokong/lean-osx,leanprover-community/lean,UlrikBuchholtz/lean,dselsam/lean,Kha/lean,rlewis1988/lean,rlewis1988/lean,soonhokong/lean,avigad/lean,htzh/lean,leanprover/lean,digama0/lean,UlrikBuchholtz/lean,soonhokong/lean,Kha/lean,avigad/lean,Kha/lean,sp3ctum/lean,leodemoura/lean,rlewis1988/lean,c-cube/lean,levnach/lean,avigad/lean,levnach/lean,soonhokong/lean-windows,soonhokong/lean-osx,eigengrau/lean,soonhokong/lean,levnach/lean,fpvandoorn/lean2,leodemoura/lean,fpvandoorn/lean2,johoelzl/lean,digama0/lean,dselsam/lean,levnach/lean,leanprover/lean,fpvandoorn/lean2,fgdorais/lean,dselsam/lean,soonhokong/lean-windows,javra/lean,leodemoura/lean,javra/lean,leodemoura/lean,eigengrau/lean,c-cube/lean,leanprover-community/lean,soonhokong/lean-windows,digama0/lean,leanprover-community/lean,c-cube/lean,rlewis1988/lean,htzh/lean,UlrikBuchholtz/lean,digama0/lean,avigad/lean,fpvandoorn/lean,dselsam/lean,javra/lean,soonhokong/lean-osx,fpvandoorn/lean,leodemoura/lean,c-cube/lean,johoelzl/lean,leanprover-community/lean,fgdorais/lean,UlrikBuchholtz/lean,rlewis1988/lean,fpvandoorn/lean,dselsam/lean,leanprover/lean,eigengrau/lean,Kha/lean,johoelzl/lean,leanprover-community/lean,rlewis1988/lean,soonhokong/lean-osx,sp3ctum/lean,UlrikBuchholtz/lean,soonhokong/lean-windows,htzh/lean,fgdorais/lean,soonhokong/lean-osx,johoelzl/lean,soonhokong/lean,javra/lean,johoelzl/lean,digama0/lean,leanprover/lean,javra/lean,soonhokong/lean-windows,Kha/lean,htzh/lean,fpvandoorn/lean,levnach/lean,avigad/lean