Do shallow testing of backend templates.
Do shallow testing of backend templates.

Just render the templates without the actual workflow to see if they
don't return a 500 error; this lets us catch various classes of
template bugs automatically.

Fixes #784.

krtkmj/zulip,peiwei/zulip,Jianchun1/zulip,tommyip/zulip,vikas-parashar/zulip,Jianchun1/zulip,PhilSk/zulip,peguin40/zulip,blaze225/zulip,dawran6/zulip,tommyip/zulip,Juanvulcano/zulip,grave-w-grave/zulip,shubhamdhama/zulip,SmartPeople/zulip,zulip/zulip,joyhchen/zulip,joyhchen/zulip,AZtheAsian/zulip,ahmadassaf/zulip,JPJPJPOPOP/zulip,brockwhittaker/zulip,kou/zulip,Diptanshu8/zulip,isht3/zulip,krtkmj/zulip,eeshangarg/zulip,jphilipsen05/zulip,niftynei/zulip,eeshangarg/zulip,shubhamdhama/zulip,Diptanshu8/zulip,zacps/zulip,JPJPJPOPOP/zulip,amyliu345/zulip,rishig/zulip,synicalsyntax/zulip,Jianchun1/zulip,Galexrt/zulip,tommyip/zulip,christi3k/zulip,jackrzhang/zulip,aakash-cr7/zulip,vaidap/zulip,susansls/zulip,PhilSk/zulip,Jianchun1/zulip,timabbott/zulip,souravbadami/zulip,calvinleenyc/zulip,peiwei/zulip,calvinleenyc/zulip,sonali0901/zulip,cosmicAsymmetry/zulip,zulip/zulip,JPJPJPOPOP/zulip,Vallher/zulip,samatdav/zulip,jackrzhang/zulip,j831/zulip,KingxBanana/zulip,shubhamdhama/zulip,peguin40/zulip,rishig/zulip,kou/zulip,kou/zulip,ryanbackman/zulip,vabs22/zulip,rht/zulip,AZtheAsian/zulip,dhcrzf/zulip,aakash-cr7/zulip,vikas-parashar/zulip,punchagan/zulip,christi3k/zulip,reyha/zulip,jphilipsen05/zulip,Juanvulcano/zulip,amanharitsh123/zulip,zulip/zulip,umkay/zulip,Vallher/zulip,souravbadami/zulip,tommyip/zulip,Juanvulcano/zulip,punchagan/zulip,zacps/zulip,j831/zulip,Juanvulcano/zulip,TigorC/zulip,eeshangarg/zulip,blaze225/zulip,cosmicAsymmetry/zulip,KingxBanana/zulip,amyliu345/zulip,dattatreya303/zulip,mohsenSy/zulip,KingxBanana/zulip,mahim97/zulip,joyhchen/zulip,jackrzhang/zulip,samatdav/zulip,umkay/zulip,Vallher/zulip,synicalsyntax/zulip,mahim97/zulip,sup95/zulip,Galexrt/zulip,jrowan/zulip,synicalsyntax/zulip,ryanbackman/zulip,souravbadami/zulip,sup95/zulip,synicalsyntax/zulip,JPJPJPOPOP/zulip,TigorC/zulip,brainwane/zulip,rht/zulip,vikas-parashar/zulip,rht/zulip,grave-w-grave/zulip,umkay/zulip,reyha/zulip,susansls/zulip,sup95/zulip,brainwane/zulip,mahim97/zulip,calvinleenyc/zulip,paxapy/zulip,brainwane/zulip,amanharitsh123/zulip,jphilipsen05/zulip,dattatreya303/zulip,brockwhittaker/zulip,verma-varsha/zulip,amanharitsh123/zulip,niftynei/zulip,joyhchen/zulip,jrowan/zulip,amanharitsh123/zulip,brainwane/zulip,christi3k/zulip,tommyip/zulip,dhcrzf/zulip,mohsenSy/zulip,cosmicAsymmetry/zulip,vaidap/zulip,Diptanshu8/zulip,SmartPeople/zulip,punchagan/zulip,jackrzhang/zulip,peiwei/zulip,arpith/zulip,AZtheAsian/zulip,kou/zulip,verma-varsha/zulip,peguin40/zulip,shubhamdhama/zulip,zulip/zulip,sharmaeklavya2/zulip,peiwei/zulip,blaze225/zulip,sup95/zulip,j831/zulip,cosmicAsymmetry/zulip,sonali0901/zulip,rishig/zulip,showell/zulip,amanharitsh123/zulip,verma-varsha/zulip,amyliu345/zulip,souravbadami/zulip,niftynei/zulip,niftynei/zulip,jackrzhang/zulip,aakash-cr7/zulip,shubhamdhama/zulip,vikas-parashar/zulip,Vallher/zulip,jrowan/zulip,christi3k/zulip,PhilSk/zulip,punchagan/zulip,andersk/zulip,jrowan/zulip,showell/zulip,isht3/zulip,dattatreya303/zulip,Diptanshu8/zulip,susansls/zulip,dattatreya303/zulip,PhilSk/zulip,grave-w-grave/zulip,jrowan/zulip,dawran6/zulip,calvinleenyc/zulip,grave-w-grave/zulip,timabbott/zulip,timabbott/zulip,dhcrzf/zulip,synicalsyntax/zulip,mohsenSy/zulip,rishig/zulip,dhcrzf/zulip,ryanbackman/zulip,Vallher/zulip,peiwei/zulip,paxapy/zulip,ryanbackman/zulip,peiwei/zulip,vikas-parashar/zulip,andersk/zulip,Juanvulcano/zulip,vabs22/zulip,sonali0901/zulip,rishig/zulip,dhcrzf/zulip,souravbadami/zulip,andersk/zulip,kou/zulip,TigorC/zulip,arpith/zulip,Diptanshu8/zulip,PhilSk/zulip,andersk/zulip,isht3/zulip,sharmaeklavya2/zulip,jainayush975/zulip,zacps/zulip,aakash-cr7/zulip,andersk/zulip,dattatreya303/zulip,vabs22/zulip,jackrzhang/zulip,JPJPJPOPOP/zulip,krtkmj/zulip,punchagan/zulip,sharmaeklavya2/zulip,calvinleenyc/zulip,isht3/zulip,brainwane/zulip,zulip/zulip,showell/zulip,jphilipsen05/zulip,j831/zulip,krtkmj/zulip,showell/zulip,KingxBanana/zulip,joyhchen/zulip,vaidap/zulip,brainwane/zulip,paxapy/zulip,showell/zulip,jrowan/zulip,grave-w-grave/zulip,mohsenSy/zulip,aakash-cr7/zulip,amyliu345/zulip,arpith/zulip,tommyip/zulip,sup95/zulip,verma-varsha/zulip,hackerkid/zulip,synicalsyntax/zulip,hackerkid/zulip,niftynei/zulip,timabbott/zulip,ahmadassaf/zulip,jainayush975/zulip,blaze225/zulip,dhcrzf/zulip,hackerkid/zulip,samatdav/zulip,vaidap/zulip,dawran6/zulip,timabbott/zulip,jphilipsen05/zulip,peguin40/zulip,timabbott/zulip,KingxBanana/zulip,brockwhittaker/zulip,Vallher/zulip,krtkmj/zulip,Jianchun1/zulip,peguin40/zulip,samatdav/zulip,verma-varsha/zulip,sharmaeklavya2/zulip,ahmadassaf/zulip,SmartPeople/zulip,zacps/zulip,mohsenSy/zulip,rht/zulip,ahmadassaf/zulip,jainayush975/zulip,KingxBanana/zulip,AZtheAsian/zulip,Jianchun1/zulip,vabs22/zulip,ryanbackman/zulip,hackerkid/zulip,reyha/zulip,mahim97/zulip,zulip/zulip,joyhchen/zulip,SmartPeople/zulip,shubhamdhama/zulip,vikas-parashar/zulip,ahmadassaf/zulip,verma-varsha/zulip,punchagan/zulip,sup95/zulip,andersk/zulip,dawran6/zulip,blaze225/zulip,peiwei/zulip,Galexrt/zulip,paxapy/zulip,cosmicAsymmetry/zulip,samatdav/zulip,eeshangarg/zulip,timabbott/zulip,Galexrt/zulip,eeshangarg/zulip,samatdav/zulip,hackerkid/zulip,tommyip/zulip,dattatreya303/zulip,Galexrt/zulip,eeshangarg/zulip,mohsenSy/zulip,arpith/zulip,umkay/zulip,vabs22/zulip,brockwhittaker/zulip,grave-w-grave/zulip,TigorC/zulip,jainayush975/zulip,sonali0901/zulip,umkay/zulip,paxapy/zulip,Galexrt/zulip,ryanbackman/zulip,peguin40/zulip,reyha/zulip,rishig/zulip,vaidap/zulip,sonali0901/zulip,isht3/zulip,punchagan/zulip,eeshangarg/zulip,susansls/zulip,andersk/zulip,aakash-cr7/zulip,dawran6/zulip,SmartPeople/zulip,TigorC/zulip,niftynei/zulip,rht/zulip,blaze225/zulip,amyliu345/zulip,amyliu345/zulip,sharmaeklavya2/zulip,krtkmj/zulip,christi3k/zulip,AZtheAsian/zulip,reyha/zulip,jainayush975/zulip,zacps/zulip,JPJPJPOPOP/zulip,arpith/zulip,Juanvulcano/zulip,hackerkid/zulip,PhilSk/zulip,paxapy/zulip,kou/zulip,hackerkid/zulip,susansls/zulip,Diptanshu8/zulip,Vallher/zulip,isht3/zulip,jackrzhang/zulip,krtkmj/zulip,mahim97/zulip,showell/zulip,rishig/zulip,souravbadami/zulip,susansls/zulip,mahim97/zulip,jainayush975/zulip,kou/zulip,j831/zulip,shubhamdhama/zulip,vaidap/zulip,sonali0901/zulip,brockwhittaker/zulip,synicalsyntax/zulip,umkay/zulip,AZtheAsian/zulip,ahmadassaf/zulip,sharmaeklavya2/zulip,amanharitsh123/zulip,TigorC/zulip,showell/zulip,calvinleenyc/zulip,zulip/zulip,jphilipsen05/zulip,rht/zulip,brockwhittaker/zulip,umkay/zulip,SmartPeople/zulip,ahmadassaf/zulip,cosmicAsymmetry/zulip,rht/zulip,arpith/zulip,brainwane/zulip,reyha/zulip,christi3k/zulip,Galexrt/zulip,dawran6/zulip,zacps/zulip,dhcrzf/zulip,vabs22/zulip,j831/zulip