Fail the script task when page URL load fails
Fail the script task when page URL load fails

It's confusing that specifying a nonexistent file on the command line just
gives me a blank page.  Until we have a real 404 page let's just crash.

AnthonyBroadCrawford/servo,saneyuki/servo,CJ8664/servo,szeged/servo,bjwbell/servo,larsbergstrom/servo,rixrix/servo,jdramani/servo,szeged/servo,dagnir/servo,peterjoel/servo,canaltinova/servo,WriterOfAlicrow/servo,mrobinson/servo,ryancanhelpyou/servo,RenaudParis/servo,g-k/servo,DominoTree/servo,aweinstock314/servo,snf/servo,hyowon/servo,thiagopnts/servo,snf/servo,larsbergstrom/servo,paulrouget/servo,RenaudParis/servo,bjwbell/servo,nerith/servo,metajack/servo,emilio/servo,DominoTree/servo,ryancanhelpyou/servo,mbrubeck/servo,caldwell/servo,evilpie/servo,wpgallih/servo,DominoTree/servo,codemac/servo,juzer10/servo,caldwell/servo,echochamber/servo,mbrubeck/servo,szeged/servo,emilio/servo,zhangjunlei26/servo,upsuper/servo,emilio/servo,michaelwu/servo,echochamber/servo,brson/servo,KiChjang/servo,szeged/servo,brson/servo,zentner-kyle/servo,rixrix/servo,ConnorGBrewster/servo,brson/servo,brendandahl/servo,jimberlage/servo,tafia/servo,dmarcos/servo,emilio/servo,samfoo/servo,AnthonyBroadCrawford/servo,owaspjocur/servo,AnthonyBroadCrawford/servo,nick-thompson/servo,pgonda/servo,evilpie/servo,boghison/servo,paulrouget/servo,froydnj/servo,AnthonyBroadCrawford/servo,saneyuki/servo,ConnorGBrewster/servo,dati91/servo,dvberkel/servo,snf/servo,codemac/servo,bfrohs/servo,eddyb/servo,srbhklkrn/SERVOENGINE,bfrohs/servo,zentner-kyle/servo,shrenikgala/servo,pyfisch/servo,shrenikgala/servo,CJ8664/servo,dvberkel/servo,nnethercote/servo,tempbottle/servo,sadmansk/servo,jdramani/servo,rixrix/servo,owaspjocur/servo,AnthonyBroadCrawford/servo,GreenRecycleBin/servo,mattnenterprise/servo,brendandahl/servo,KiChjang/servo,jgraham/servo,pyfisch/servo,ConnorGBrewster/servo,caldwell/servo,samfoo/servo,huonw/servo,jimberlage/servo,Aalhad/CanvasRenderingContext2DMozilla,tafia/servo,michaelwu/servo,kindersung/servo,splav/servo,aidanhs/servo,indykish/servo,fiji-flo/servo,rixrix/servo,dati91/servo,wartman4404/servo,pyecs/servo,nrc/servo,wartman4404/servo,seanmonstar/servo,caldwell/servo,saratang/servo,mrobinson/servo,echochamber/servo,fiji-flo/servo,dvberkel/servo,tschneidereit/servo,nerith/servo,j3parker/servo,bjwbell/servo,srbhklkrn/SERVOENGINE,hyowon/servo,dvberkel/servo,zhangjunlei26/servo,indykish/servo,GyrosOfWar/servo,avadacatavra/servo,g-k/servo,nerith/servo,dsandeephegde/servo,owaspjocur/servo,GreenRecycleBin/servo,michaelwu/servo,A-deLuna/servo,emilio/servo,cbrewster/servo,thiagopnts/servo,upsuper/servo,tempbottle/servo,saneyuki/servo,nrc/servo,metajack/servo,runarberg/servo,deokjinkim/servo,wpgallih/servo,michaelwu/servo,pyfisch/servo,ryancanhelpyou/servo,samfoo/servo,saneyuki/servo,GyrosOfWar/servo,j3parker/servo,srbhklkrn/SERVOENGINE,fiji-flo/servo,bjwbell/servo,tempbottle/servo,saneyuki/servo,dmarcos/servo,dmarcos/servo,szeged/servo,saratang/servo,WriterOfAlicrow/servo,owaspjocur/servo,g-k/servo,ryancanhelpyou/servo,canaltinova/servo,CJ8664/servo,pyecs/servo,zentner-kyle/servo,dsandeephegde/servo,Aalhad/CanvasRenderingContext2DMozilla,Shraddha512/servo,rentongzhang/servo,shrenikgala/servo,wpgallih/servo,eddyb/servo,notriddle/servo,pgonda/servo,echochamber/servo,jimberlage/servo,g-k/servo,mattnenterprise/servo,runarberg/servo,juzer10/servo,kindersung/servo,mt2d2/servo,canaltinova/servo,GreenRecycleBin/servo,szeged/servo,dati91/servo,karlito40/servo,shrenikgala/servo,brendandahl/servo,dsandeephegde/servo,codemac/servo,mdibaiee/servo,peterjoel/servo,evilpie/servo,rnestler/servo,snf/servo,AnthonyBroadCrawford/servo,luniv/servo,SimonSapin/servo,g-k/servo,tafia/servo,bfrohs/servo,nnethercote/servo,nick-thompson/servo,DominoTree/servo,canaltinova/servo,dati91/servo,zentner-kyle/servo,michaelwu/servo,saratang/servo,hyowon/servo,emilio/servo,jlegendary/servo,Aalhad/CanvasRenderingContext2DMozilla,kindersung/servo,nnethercote/servo,dhananjay92/servo,RenaudParis/servo,walac/servo,wpgallih/servo,jimberlage/servo,jimberlage/servo,ConnorGBrewster/servo,anthgur/servo,wartman4404/servo,nnethercote/servo,juzer10/servo,pgonda/servo,dagnir/servo,A-deLuna/servo,tschneidereit/servo,Shraddha512/servo,jdramani/servo,huonw/servo,tschneidereit/servo,Shraddha512/servo,meh/servo,j3parker/servo,metajack/servo,pyecs/servo,splav/servo,steveklabnik/servo,mukilan/servo,seanmonstar/servo,paulrouget/servo,youprofit/servo,CJ8664/servo,GreenRecycleBin/servo,pcwalton/servo,zentner-kyle/servo,eddyb/servo,codemac/servo,walac/servo,youprofit/servo,metajack/servo,saratang/servo,dvberkel/servo,dhananjay92/servo,echochamber/servo,saratang/servo,DominoTree/servo,fiji-flo/servo,metajack/servo,larsbergstrom/servo,zhangjunlei26/servo,pgonda/servo,Shraddha512/servo,tafia/servo,s142857/servo,A-deLuna/servo,dmarcos/servo,jdramani/servo,canaltinova/servo,mattnenterprise/servo,canaltinova/servo,dmarcos/servo,paulrouget/servo,ConnorGBrewster/servo,snf/servo,nnethercote/servo,g-k/servo,mt2d2/servo,aidanhs/servo,youprofit/servo,SimonSapin/servo,aweinstock314/servo,g-k/servo,steveklabnik/servo,steveklabnik/servo,brendandahl/servo,mbrubeck/servo,caldwell/servo,chotchki/servo,notriddle/servo,brson/servo,dati91/servo,notriddle/servo,rentongzhang/servo,youprofit/servo,SimonSapin/servo,anthgur/servo,dhananjay92/servo,evilpie/servo,GyrosOfWar/servo,nnethercote/servo,cbrewster/servo,emilio/servo,zhangjunlei26/servo,wartman4404/servo,jgraham/servo,rnestler/servo,froydnj/servo,cbrewster/servo,splav/servo,samfoo/servo,notriddle/servo,vks/servo,mrobinson/servo,pyfisch/servo,rixrix/servo,mattnenterprise/servo,dhananjay92/servo,bjwbell/servo,thiagopnts/servo,aweinstock314/servo,GyrosOfWar/servo,youprofit/servo,larsbergstrom/servo,splav/servo,KiChjang/servo,rentongzhang/servo,pcwalton/servo,karlito40/servo,CJ8664/servo,rnestler/servo,paulrouget/servo,deokjinkim/servo,pcwalton/servo,pcwalton/servo,saneyuki/servo,GyrosOfWar/servo,rentongzhang/servo,ryancanhelpyou/servo,pyecs/servo,metajack/servo,codemac/servo,nrc/servo,shrenikgala/servo,saneyuki/servo,codemac/servo,larsbergstrom/servo,huonw/servo,s142857/servo,thiagopnts/servo,mt2d2/servo,seanmonstar/servo,paulrouget/servo,bfrohs/servo,zentner-kyle/servo,mattnenterprise/servo,Adenilson/prototype-viewing-distance,snf/servo,chotchki/servo,ruud-v-a/servo,nick-thompson/servo,dvberkel/servo,akosel/servo,mdibaiee/servo,steveklabnik/servo,saratang/servo,AnthonyBroadCrawford/servo,ryancanhelpyou/servo,juzer10/servo,Shraddha512/servo,Adenilson/prototype-viewing-distance,akosel/servo,hyowon/servo,dsandeephegde/servo,hyowon/servo,A-deLuna/servo,anthgur/servo,pyfisch/servo,runarberg/servo,nerith/servo,CJ8664/servo,dmarcos/servo,indykish/servo,dati91/servo,youprofit/servo,jgraham/servo,pyecs/servo,WriterOfAlicrow/servo,steveklabnik/servo,SimonSapin/servo,juzer10/servo,juzer10/servo,nick-thompson/servo,WriterOfAlicrow/servo,vks/servo,wpgallih/servo,dagnir/servo,indykish/servo,evilpie/servo,owaspjocur/servo,brson/servo,splav/servo,SimonSapin/servo,larsbergstrom/servo,emilio/servo,mukilan/servo,evilpie/servo,steveklabnik/servo,aidanhs/servo,mattnenterprise/servo,cbrewster/servo,hyowon/servo,seanmonstar/servo,pyfisch/servo,nrc/servo,pcwalton/servo,avadacatavra/servo,nerith/servo,deokjinkim/servo,saneyuki/servo,srbhklkrn/SERVOENGINE,larsbergstrom/servo,vks/servo,GreenRecycleBin/servo,upsuper/servo,bfrohs/servo,dagnir/servo,peterjoel/servo,KiChjang/servo,zentner-kyle/servo,GreenRecycleBin/servo,pyfisch/servo,meh/servo,evilpie/servo,vks/servo,cbrewster/servo,Adenilson/prototype-viewing-distance,hyowon/servo,walac/servo,meh/servo,dati91/servo,kindersung/servo,larsbergstrom/servo,pgonda/servo,thiagopnts/servo,fiji-flo/servo,karlito40/servo,mdibaiee/servo,upsuper/servo,notriddle/servo,dhananjay92/servo,ruud-v-a/servo,mt2d2/servo,shrenikgala/servo,notriddle/servo,Adenilson/prototype-viewing-distance,boghison/servo,DominoTree/servo,notriddle/servo,saneyuki/servo,brendandahl/servo,jimberlage/servo,dagnir/servo,CJ8664/servo,avadacatavra/servo,meh/servo,mbrubeck/servo,ryancanhelpyou/servo,szeged/servo,j3parker/servo,codemac/servo,jdramani/servo,GyrosOfWar/servo,pcwalton/servo,kindersung/servo,meh/servo,dmarcos/servo,caldwell/servo,KiChjang/servo,pyecs/servo,A-deLuna/servo,mrobinson/servo,indykish/servo,fiji-flo/servo,jlegendary/servo,avadacatavra/servo,wartman4404/servo,mbrubeck/servo,WriterOfAlicrow/servo,tempbottle/servo,sadmansk/servo,rentongzhang/servo,chotchki/servo,akosel/servo,dsandeephegde/servo,meh/servo,rixrix/servo,DominoTree/servo,rnestler/servo,pyfisch/servo,ConnorGBrewster/servo,runarberg/servo,upsuper/servo,GreenRecycleBin/servo,thiagopnts/servo,sadmansk/servo,tschneidereit/servo,thiagopnts/servo,mattnenterprise/servo,tafia/servo,aidanhs/servo,anthgur/servo,upsuper/servo,KiChjang/servo,jlegendary/servo,SimonSapin/servo,aidanhs/servo,sadmansk/servo,kindersung/servo,KiChjang/servo,tschneidereit/servo,eddyb/servo,zhangjunlei26/servo,jgraham/servo,DominoTree/servo,notriddle/servo,splav/servo,echochamber/servo,DominoTree/servo,evilpie/servo,tempbottle/servo,luniv/servo,bfrohs/servo,mdibaiee/servo,nrc/servo,CJ8664/servo,saratang/servo,larsbergstrom/servo,deokjinkim/servo,michaelwu/servo,luniv/servo,akosel/servo,szeged/servo,avadacatavra/servo,peterjoel/servo,rixrix/servo,nnethercote/servo,peterjoel/servo,mt2d2/servo,s142857/servo,zhangjunlei26/servo,runarberg/servo,rixrix/servo,evilpie/servo,mdibaiee/servo,s142857/servo,jlegendary/servo,paulrouget/servo,mt2d2/servo,aweinstock314/servo,rnestler/servo,luniv/servo,wpgallih/servo,tempbottle/servo,dhananjay92/servo,Aalhad/CanvasRenderingContext2DMozilla,canaltinova/servo,notriddle/servo,avadacatavra/servo,SimonSapin/servo,eddyb/servo,nerith/servo,froydnj/servo,mdibaiee/servo,samfoo/servo,boghison/servo,RenaudParis/servo,shrenikgala/servo,samfoo/servo,nick-thompson/servo,Adenilson/prototype-viewing-distance,caldwell/servo,kindersung/servo,akosel/servo,bjwbell/servo,zhangjunlei26/servo,cbrewster/servo,pyfisch/servo,nick-thompson/servo,Aalhad/CanvasRenderingContext2DMozilla,paulrouget/servo,pgonda/servo,eddyb/servo,juzer10/servo,peterjoel/servo,dati91/servo,pyecs/servo,s142857/servo,chotchki/servo,mukilan/servo,rnestler/servo,nnethercote/servo,jimberlage/servo,peterjoel/servo,aweinstock314/servo,seanmonstar/servo,deokjinkim/servo,huonw/servo,walac/servo,nerith/servo,tschneidereit/servo,peterjoel/servo,saneyuki/servo,srbhklkrn/SERVOENGINE,rentongzhang/servo,dhananjay92/servo,jlegendary/servo,froydnj/servo,Shraddha512/servo,jlegendary/servo,walac/servo,froydnj/servo,anthgur/servo,sadmansk/servo,thiagopnts/servo,anthgur/servo,huonw/servo,anthgur/servo,nnethercote/servo,jgraham/servo,sadmansk/servo,walac/servo,indykish/servo,A-deLuna/servo,ConnorGBrewster/servo,s142857/servo,boghison/servo,vks/servo,ruud-v-a/servo,avadacatavra/servo,splav/servo,tschneidereit/servo,mbrubeck/servo,dvberkel/servo,aidanhs/servo,brendandahl/servo,jimberlage/servo,peterjoel/servo,owaspjocur/servo,cbrewster/servo,GreenRecycleBin/servo,eddyb/servo,upsuper/servo,meh/servo,jgraham/servo,szeged/servo,deokjinkim/servo,indykish/servo,KiChjang/servo,mdibaiee/servo,RenaudParis/servo,vks/servo,emilio/servo,peterjoel/servo,A-deLuna/servo,Shraddha512/servo,jimberlage/servo,seanmonstar/servo,Adenilson/prototype-viewing-distance,nrc/servo,splav/servo,splav/servo,wpgallih/servo,Adenilson/prototype-viewing-distance,deokjinkim/servo,brendandahl/servo,tafia/servo,dagnir/servo,DominoTree/servo,srbhklkrn/SERVOENGINE,karlito40/servo,cbrewster/servo,mukilan/servo,snf/servo,indykish/servo,tempbottle/servo,echochamber/servo,luniv/servo,notriddle/servo,rnestler/servo,steveklabnik/servo,srbhklkrn/SERVOENGINE,rnestler/servo,jdramani/servo,akosel/servo,mt2d2/servo,indykish/servo,szeged/servo,nrc/servo,RenaudParis/servo,brson/servo,dsandeephegde/servo,mrobinson/servo,mbrubeck/servo,zhangjunlei26/servo,boghison/servo,zhangjunlei26/servo,bjwbell/servo,canaltinova/servo,wartman4404/servo,pyfisch/servo,fiji-flo/servo,mukilan/servo,rixrix/servo,mattnenterprise/servo,rentongzhang/servo,sadmansk/servo,pgonda/servo,karlito40/servo,j3parker/servo,KiChjang/servo,mrobinson/servo,ruud-v-a/servo,nnethercote/servo,dsandeephegde/servo,runarberg/servo,jdramani/servo,wpgallih/servo,froydnj/servo,jgraham/servo,boghison/servo,paulrouget/servo,luniv/servo,mbrubeck/servo,RenaudParis/servo,ruud-v-a/servo,huonw/servo,WriterOfAlicrow/servo,vks/servo,GyrosOfWar/servo,SimonSapin/servo,boghison/servo,huonw/servo,sadmansk/servo,samfoo/servo,j3parker/servo,WriterOfAlicrow/servo,paulrouget/servo,aweinstock314/servo,youprofit/servo,eddyb/servo,mukilan/servo,Aalhad/CanvasRenderingContext2DMozilla,luniv/servo,ConnorGBrewster/servo,dsandeephegde/servo,aweinstock314/servo,akosel/servo,avadacatavra/servo,ruud-v-a/servo,karlito40/servo,tafia/servo,wartman4404/servo,splav/servo,s142857/servo,j3parker/servo,dagnir/servo,upsuper/servo,karlito40/servo,fiji-flo/servo,jlegendary/servo,GreenRecycleBin/servo,larsbergstrom/servo,KiChjang/servo,nick-thompson/servo,walac/servo,chotchki/servo,chotchki/servo,aidanhs/servo,wpgallih/servo,runarberg/servo,emilio/servo,anthgur/servo