Auto merge of #19740 - servo:jdm-patch-2, r=aneeshusa
Auto merge of #19740 - servo:jdm-patch-2, r=aneeshusa

Allow warnings during mutation tests.

Sometimes mutations include removing the only use of a variable. When we deny warnings globally, we inhibit these mutations that trigger new warnings.

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