chore(frontends/lean/elaborator): remove dead code
chore(frontends/lean/elaborator): remove dead code

Signed-off-by: Leonardo de Moura <7610bae85f2b530654cc716772f1fe653373e892@microsoft.com>

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