Record reference test stdout and stderr
Record reference test stdout and stderr

When reference tests crash it is difficult to debug the issue, because
the stacktrace and any other output is discarded by the test harness.
Instead of discarding it, write the output to text files in the test
results directory which will make it easier to debug crashing tests.

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