script: Don't paint layouts induced by hit test queries.
script: Don't paint layouts induced by hit test queries.

Reduces CPU usage when mousing over simple pages.

Part of #9999.

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