Stop using [T]::tail.
Stop using [T]::tail.

It has been removed upstream (rust-lang/rust#27684).

bjwbell/servo,pyfisch/servo,meh/servo,avadacatavra/servo,larsbergstrom/servo,KiChjang/servo,dvberkel/servo,kindersung/servo,sadmansk/servo,rnestler/servo,akosel/servo,avadacatavra/servo,mattnenterprise/servo,jdramani/servo,notriddle/servo,canaltinova/servo,SimonSapin/servo,runarberg/servo,CJ8664/servo,tafia/servo,peterjoel/servo,KiChjang/servo,dagnir/servo,bjwbell/servo,jimberlage/servo,upsuper/servo,sadmansk/servo,upsuper/servo,rentongzhang/servo,RenaudParis/servo,jlegendary/servo,canaltinova/servo,splav/servo,jlegendary/servo,dvberkel/servo,mattnenterprise/servo,paulrouget/servo,notriddle/servo,A-deLuna/servo,dati91/servo,upsuper/servo,saneyuki/servo,GyrosOfWar/servo,jimberlage/servo,rnestler/servo,dati91/servo,bjwbell/servo,nrc/servo,A-deLuna/servo,meh/servo,pyfisch/servo,szeged/servo,caldwell/servo,SimonSapin/servo,paulrouget/servo,saneyuki/servo,larsbergstrom/servo,wartman4404/servo,codemac/servo,notriddle/servo,jdramani/servo,dsandeephegde/servo,dsandeephegde/servo,SimonSapin/servo,wartman4404/servo,notriddle/servo,huonw/servo,eddyb/servo,dati91/servo,dati91/servo,cbrewster/servo,codemac/servo,mbrubeck/servo,nnethercote/servo,RenaudParis/servo,j3parker/servo,pyfisch/servo,KiChjang/servo,mbrubeck/servo,splav/servo,KiChjang/servo,notriddle/servo,akosel/servo,paulrouget/servo,cbrewster/servo,dsandeephegde/servo,j3parker/servo,walac/servo,huonw/servo,mattnenterprise/servo,AnthonyBroadCrawford/servo,jimberlage/servo,bjwbell/servo,saratang/servo,rnestler/servo,A-deLuna/servo,szeged/servo,dsandeephegde/servo,dsandeephegde/servo,meh/servo,saratang/servo,paulrouget/servo,emilio/servo,aidanhs/servo,GyrosOfWar/servo,peterjoel/servo,jimberlage/servo,saneyuki/servo,upsuper/servo,WriterOfAlicrow/servo,caldwell/servo,larsbergstrom/servo,brendandahl/servo,thiagopnts/servo,tafia/servo,dagnir/servo,caldwell/servo,youprofit/servo,splav/servo,dagnir/servo,AnthonyBroadCrawford/servo,saratang/servo,DominoTree/servo,thiagopnts/servo,walac/servo,meh/servo,huonw/servo,SimonSapin/servo,cbrewster/servo,larsbergstrom/servo,cbrewster/servo,youprofit/servo,cbrewster/servo,aidanhs/servo,jimberlage/servo,emilio/servo,rentongzhang/servo,ConnorGBrewster/servo,kindersung/servo,akosel/servo,pyfisch/servo,jdramani/servo,nrc/servo,ConnorGBrewster/servo,thiagopnts/servo,saratang/servo,mbrubeck/servo,fiji-flo/servo,runarberg/servo,AnthonyBroadCrawford/servo,nnethercote/servo,eddyb/servo,youprofit/servo,thiagopnts/servo,brendandahl/servo,huonw/servo,DominoTree/servo,nnethercote/servo,walac/servo,WriterOfAlicrow/servo,eddyb/servo,rentongzhang/servo,upsuper/servo,peterjoel/servo,wartman4404/servo,splav/servo,paulrouget/servo,larsbergstrom/servo,mattnenterprise/servo,pyfisch/servo,anthgur/servo,KiChjang/servo,thiagopnts/servo,tafia/servo,jlegendary/servo,wartman4404/servo,jlegendary/servo,szeged/servo,CJ8664/servo,WriterOfAlicrow/servo,A-deLuna/servo,kindersung/servo,sadmansk/servo,mdibaiee/servo,canaltinova/servo,mattnenterprise/servo,emilio/servo,saneyuki/servo,brendandahl/servo,rentongzhang/servo,KiChjang/servo,brendandahl/servo,CJ8664/servo,emilio/servo,emilio/servo,peterjoel/servo,GyrosOfWar/servo,caldwell/servo,eddyb/servo,anthgur/servo,dvberkel/servo,DominoTree/servo,RenaudParis/servo,caldwell/servo,rnestler/servo,szeged/servo,tafia/servo,dsandeephegde/servo,splav/servo,peterjoel/servo,pyfisch/servo,tafia/servo,KiChjang/servo,notriddle/servo,KiChjang/servo,akosel/servo,youprofit/servo,fiji-flo/servo,mbrubeck/servo,walac/servo,dati91/servo,dsandeephegde/servo,szeged/servo,nrc/servo,peterjoel/servo,dvberkel/servo,peterjoel/servo,splav/servo,AnthonyBroadCrawford/servo,avadacatavra/servo,jimberlage/servo,DominoTree/servo,ConnorGBrewster/servo,szeged/servo,rnestler/servo,nrc/servo,fiji-flo/servo,avadacatavra/servo,mattnenterprise/servo,sadmansk/servo,akosel/servo,peterjoel/servo,walac/servo,fiji-flo/servo,GyrosOfWar/servo,canaltinova/servo,szeged/servo,nnethercote/servo,fiji-flo/servo,kindersung/servo,avadacatavra/servo,RenaudParis/servo,aidanhs/servo,jimberlage/servo,j3parker/servo,DominoTree/servo,peterjoel/servo,meh/servo,nrc/servo,nnethercote/servo,saneyuki/servo,pyfisch/servo,WriterOfAlicrow/servo,peterjoel/servo,dati91/servo,fiji-flo/servo,steveklabnik/servo,notriddle/servo,larsbergstrom/servo,DominoTree/servo,mattnenterprise/servo,szeged/servo,wartman4404/servo,youprofit/servo,caldwell/servo,jdramani/servo,steveklabnik/servo,codemac/servo,brendandahl/servo,steveklabnik/servo,j3parker/servo,mdibaiee/servo,larsbergstrom/servo,nnethercote/servo,emilio/servo,dhananjay92/servo,saneyuki/servo,saratang/servo,thiagopnts/servo,runarberg/servo,mdibaiee/servo,j3parker/servo,mbrubeck/servo,sadmansk/servo,cbrewster/servo,larsbergstrom/servo,paulrouget/servo,paulrouget/servo,saneyuki/servo,mdibaiee/servo,szeged/servo,wartman4404/servo,WriterOfAlicrow/servo,bjwbell/servo,rnestler/servo,CJ8664/servo,SimonSapin/servo,meh/servo,aidanhs/servo,fiji-flo/servo,dhananjay92/servo,ConnorGBrewster/servo,nnethercote/servo,huonw/servo,bjwbell/servo,mattnenterprise/servo,mdibaiee/servo,dhananjay92/servo,mbrubeck/servo,saneyuki/servo,DominoTree/servo,steveklabnik/servo,avadacatavra/servo,rnestler/servo,mbrubeck/servo,tafia/servo,RenaudParis/servo,rentongzhang/servo,RenaudParis/servo,eddyb/servo,anthgur/servo,jimberlage/servo,wartman4404/servo,dvberkel/servo,aidanhs/servo,emilio/servo,codemac/servo,SimonSapin/servo,dsandeephegde/servo,emilio/servo,pyfisch/servo,avadacatavra/servo,aidanhs/servo,canaltinova/servo,dhananjay92/servo,notriddle/servo,brendandahl/servo,eddyb/servo,kindersung/servo,upsuper/servo,meh/servo,walac/servo,dagnir/servo,larsbergstrom/servo,dvberkel/servo,runarberg/servo,mdibaiee/servo,splav/servo,anthgur/servo,ConnorGBrewster/servo,jdramani/servo,cbrewster/servo,runarberg/servo,rentongzhang/servo,splav/servo,CJ8664/servo,dati91/servo,dhananjay92/servo,mdibaiee/servo,pyfisch/servo,nrc/servo,KiChjang/servo,A-deLuna/servo,sadmansk/servo,brendandahl/servo,thiagopnts/servo,dagnir/servo,notriddle/servo,akosel/servo,youprofit/servo,saneyuki/servo,saratang/servo,DominoTree/servo,rentongzhang/servo,dvberkel/servo,paulrouget/servo,mbrubeck/servo,saneyuki/servo,WriterOfAlicrow/servo,eddyb/servo,sadmansk/servo,splav/servo,GyrosOfWar/servo,nnethercote/servo,dhananjay92/servo,dhananjay92/servo,fiji-flo/servo,CJ8664/servo,DominoTree/servo,CJ8664/servo,notriddle/servo,canaltinova/servo,eddyb/servo,upsuper/servo,AnthonyBroadCrawford/servo,SimonSapin/servo,ConnorGBrewster/servo,jlegendary/servo,nnethercote/servo,akosel/servo,emilio/servo,GyrosOfWar/servo,kindersung/servo,jimberlage/servo,saratang/servo,KiChjang/servo,aidanhs/servo,jlegendary/servo,A-deLuna/servo,kindersung/servo,cbrewster/servo,A-deLuna/servo,jdramani/servo,tafia/servo,avadacatavra/servo,youprofit/servo,runarberg/servo,nnethercote/servo,ConnorGBrewster/servo,WriterOfAlicrow/servo,GyrosOfWar/servo,RenaudParis/servo,steveklabnik/servo,canaltinova/servo,anthgur/servo,walac/servo,dagnir/servo,canaltinova/servo,codemac/servo,splav/servo,anthgur/servo,anthgur/servo,j3parker/servo,upsuper/servo,runarberg/servo,huonw/servo,larsbergstrom/servo,rnestler/servo,jdramani/servo,paulrouget/servo,SimonSapin/servo,steveklabnik/servo,j3parker/servo,codemac/servo,CJ8664/servo,bjwbell/servo,paulrouget/servo,nrc/servo,dagnir/servo,AnthonyBroadCrawford/servo,jlegendary/servo,emilio/servo,caldwell/servo,DominoTree/servo,AnthonyBroadCrawford/servo,szeged/servo,anthgur/servo,steveklabnik/servo,sadmansk/servo,huonw/servo,codemac/servo,pyfisch/servo,thiagopnts/servo,ConnorGBrewster/servo,dati91/servo