Auto merge of #10094 - KiChjang:remove-extra-iter, r=asajeffrey
Auto merge of #10094 - KiChjang:remove-extra-iter, r=asajeffrey

Remove HTMLCollectionElementsRevIter

It's almost a duplicate of HTMLCollectionElementsIter, aside from that its node_iter is a PrecedingNodeIter. We can simply use dynamic dispatch for node_iter instead of making it a concrete type.

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