Optimize LRUCache by using a VecDeque.
Optimize LRUCache by using a VecDeque.

We also reverse the order, so that we don't need iter.rev().

mattnenterprise/servo,thiagopnts/servo,CJ8664/servo,CJ8664/servo,paulrouget/servo,mattnenterprise/servo,canaltinova/servo,saneyuki/servo,mbrubeck/servo,fiji-flo/servo,peterjoel/servo,thiagopnts/servo,KiChjang/servo,pyfisch/servo,dsandeephegde/servo,anthgur/servo,DominoTree/servo,eddyb/servo,notriddle/servo,cbrewster/servo,jimberlage/servo,emilio/servo,anthgur/servo,ConnorGBrewster/servo,larsbergstrom/servo,upsuper/servo,peterjoel/servo,sadmansk/servo,upsuper/servo,rnestler/servo,avadacatavra/servo,peterjoel/servo,mbrubeck/servo,rnestler/servo,ConnorGBrewster/servo,saneyuki/servo,avadacatavra/servo,splav/servo,upsuper/servo,SimonSapin/servo,saneyuki/servo,peterjoel/servo,nnethercote/servo,CJ8664/servo,eddyb/servo,larsbergstrom/servo,notriddle/servo,peterjoel/servo,KiChjang/servo,avadacatavra/servo,szeged/servo,dati91/servo,canaltinova/servo,pyfisch/servo,splav/servo,emilio/servo,canaltinova/servo,jimberlage/servo,KiChjang/servo,ConnorGBrewster/servo,rnestler/servo,jimberlage/servo,DominoTree/servo,dati91/servo,dsandeephegde/servo,szeged/servo,splav/servo,notriddle/servo,nnethercote/servo,ConnorGBrewster/servo,dati91/servo,notriddle/servo,nnethercote/servo,SimonSapin/servo,rnestler/servo,avadacatavra/servo,szeged/servo,anthgur/servo,SimonSapin/servo,fiji-flo/servo,rnestler/servo,sadmansk/servo,szeged/servo,eddyb/servo,saneyuki/servo,notriddle/servo,nnethercote/servo,CJ8664/servo,CJ8664/servo,notriddle/servo,DominoTree/servo,dsandeephegde/servo,paulrouget/servo,DominoTree/servo,peterjoel/servo,avadacatavra/servo,canaltinova/servo,rnestler/servo,pyfisch/servo,fiji-flo/servo,sadmansk/servo,thiagopnts/servo,KiChjang/servo,dsandeephegde/servo,saneyuki/servo,dati91/servo,canaltinova/servo,mattnenterprise/servo,peterjoel/servo,dati91/servo,upsuper/servo,fiji-flo/servo,notriddle/servo,cbrewster/servo,anthgur/servo,mbrubeck/servo,pyfisch/servo,nnethercote/servo,canaltinova/servo,SimonSapin/servo,mattnenterprise/servo,DominoTree/servo,ConnorGBrewster/servo,saneyuki/servo,szeged/servo,larsbergstrom/servo,szeged/servo,paulrouget/servo,KiChjang/servo,mbrubeck/servo,notriddle/servo,paulrouget/servo,fiji-flo/servo,DominoTree/servo,eddyb/servo,anthgur/servo,mbrubeck/servo,larsbergstrom/servo,emilio/servo,CJ8664/servo,thiagopnts/servo,emilio/servo,CJ8664/servo,cbrewster/servo,emilio/servo,paulrouget/servo,cbrewster/servo,nnethercote/servo,KiChjang/servo,dsandeephegde/servo,emilio/servo,pyfisch/servo,dati91/servo,upsuper/servo,eddyb/servo,rnestler/servo,nnethercote/servo,paulrouget/servo,szeged/servo,nnethercote/servo,avadacatavra/servo,mbrubeck/servo,sadmansk/servo,DominoTree/servo,pyfisch/servo,emilio/servo,nnethercote/servo,mattnenterprise/servo,mattnenterprise/servo,thiagopnts/servo,fiji-flo/servo,dsandeephegde/servo,larsbergstrom/servo,splav/servo,saneyuki/servo,mbrubeck/servo,eddyb/servo,KiChjang/servo,SimonSapin/servo,larsbergstrom/servo,larsbergstrom/servo,paulrouget/servo,KiChjang/servo,peterjoel/servo,thiagopnts/servo,notriddle/servo,pyfisch/servo,splav/servo,thiagopnts/servo,ConnorGBrewster/servo,splav/servo,splav/servo,pyfisch/servo,KiChjang/servo,avadacatavra/servo,saneyuki/servo,SimonSapin/servo,avadacatavra/servo,rnestler/servo,splav/servo,canaltinova/servo,SimonSapin/servo,anthgur/servo,sadmansk/servo,larsbergstrom/servo,notriddle/servo,cbrewster/servo,ConnorGBrewster/servo,dsandeephegde/servo,mattnenterprise/servo,anthgur/servo,paulrouget/servo,larsbergstrom/servo,szeged/servo,splav/servo,jimberlage/servo,dsandeephegde/servo,sadmansk/servo,canaltinova/servo,jimberlage/servo,cbrewster/servo,pyfisch/servo,fiji-flo/servo,DominoTree/servo,paulrouget/servo,larsbergstrom/servo,szeged/servo,mattnenterprise/servo,dati91/servo,anthgur/servo,szeged/servo,emilio/servo,jimberlage/servo,peterjoel/servo,jimberlage/servo,sadmansk/servo,upsuper/servo,eddyb/servo,peterjoel/servo,CJ8664/servo,splav/servo,sadmansk/servo,cbrewster/servo,nnethercote/servo,jimberlage/servo,saneyuki/servo,dati91/servo,upsuper/servo,jimberlage/servo,emilio/servo,DominoTree/servo,saneyuki/servo,thiagopnts/servo,DominoTree/servo,mbrubeck/servo,ConnorGBrewster/servo,pyfisch/servo,SimonSapin/servo,paulrouget/servo,cbrewster/servo,emilio/servo,upsuper/servo,eddyb/servo,KiChjang/servo,fiji-flo/servo